feat: 原文中文对照（逐句）— 高亮句同色同序号对位

- /api/translate 增加逐句模式（sentences）: 前端拆句（en 为原文精确文本）→ 模型逐句翻译，
  数量/顺序校验复用 _count_check（不一致自动重试）；响应 en 原样回填保证对位可靠
- 左栏原文区新增「原文中文对照 →」: 逐句中文展示，命中批注 evidence 的句子
  与原文同色（note-rhetoric/repeat/growth/structure）+ 同序号（sup），
  点击对照行可联动高亮原文句与批注卡片
- 对照缓存按段保存并持久化（原文变化/换文书自动失效清空）
- 测试: 新增逐句模式 2 个 hermetic 测试（33 passed）
- 浏览器实测 18/18 通过（含逐句渲染/高亮对位/点击联动/刷新持久化）

index.html

@@ -82,7 +82,7 @@ button,input,textarea{font:inherit}button{cursor:pointer}.hidden{display:none!im
 
 .full-original-list{display:flex;flex-direction:column;gap:9px}.mode-note{font-size:11px;color:#9299aa;margin:0 0 2px}.full-paragraph{border:1px solid transparent;border-radius:11px;padding:12px 13px;transition:.15s;cursor:pointer;position:relative}.full-paragraph:hover{background:#fafaff;border-color:#e8e8ff}.full-paragraph.active{background:#f7f7ff;border-color:#dedfff}.full-paragraph.active:before{content:"";position:absolute;left:-1px;top:12px;bottom:12px;width:3px;border-radius:3px;background:var(--brand)}.full-paragraph-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:6px}.full-paragraph-label{font-size:11.5px;font-weight:780;color:#42485b}.full-paragraph-state{font-size:10px;color:#8f96a6}.full-paragraph.active .full-paragraph-state{color:var(--brand);font-weight:750}.full-paragraph-copy{font:13.5px/1.72 Georgia,"Times New Roman",serif;color:#4a5060;margin:0}.full-paragraph-foot{display:flex;justify-content:flex-end;margin-top:7px}.full-issues-button{border:0;background:transparent;color:#6663d9;font-size:10.5px;font-weight:750;padding:2px 0}.full-issues-button:hover{text-decoration:underline}
 
-.rewrite-card{min-height:690px}.rewrite-intro{font-size:12px;color:#737b8d;margin-bottom:12px}.rewrite-area{width:100%;min-height:500px;border:1px solid #e2e4ed;border-radius:11px;outline:0;resize:vertical;padding:15px 16px;font:15px/1.8 Georgia,"Times New Roman",serif;color:#2f3443;background:#fff;transition:.15s}.rewrite-area:focus{border-color:#b9baff;box-shadow:0 0 0 3px rgba(86,84,245,.08)}.rewrite-meta{display:flex;justify-content:space-between;gap:10px;margin-top:8px;font-size:11px;color:#9aa0ad}.word-meta.warn{color:#b45309;font-weight:700}.translate-row{margin-top:10px;display:flex;align-items:center;gap:8px}.translate-row .btn.link{font-size:11.5px;font-weight:760;padding:0}.translate-box{display:none;margin-top:8px;background:#f6f7ff;border:1px dashed #d9dcf5;border-radius:10px;padding:11px 12px;font-size:12px;color:#4c5468;line-height:1.75;white-space:pre-wrap}.translate-box.open{display:block}.translate-label{font-size:10px;color:#8b92a3;font-weight:800;margin-bottom:5px;display:block}.rewrite-help{margin-top:16px;border-top:1px solid var(--line);padding-top:13px}.help-entry{display:flex;align-items:center;gap:8px;font-size:11.5px;color:#777e8f}.help-entry .btn.link{font-size:11.5px;font-weight:760;padding:0}.help-panel{display:none;margin-top:10px;background:#fafbff;border:1px solid #e6e7f3;border-radius:10px;padding:11px 12px}.help-panel.open{display:block}.help-label{font-size:10px;color:#8b92a3;font-weight:800;margin-bottom:5px}.scaffold{font-size:12px;color:#50586a;line-height:1.7;white-space:pre-wrap}.reference-trigger{margin-top:9px;padding-top:8px;border-top:1px solid #eceef4}.reference{display:none;margin-top:8px;background:#fff;border:1px solid #e6e7ef;border-radius:8px;padding:9px 10px;font-size:11.5px;color:#596174;white-space:pre-wrap;line-height:1.7}.reference.open{display:block}.reference-note{font-size:10px;color:#9198a7;margin-top:6px}.write-tools{border-top:1px solid var(--line);padding:11px 14px;display:flex;justify-content:space-between;gap:10px;align-items:center}.nav-group{display:flex;gap:8px}.demo-hint{font-size:11px;color:#9a9fac}
+.rewrite-card{min-height:690px}.rewrite-intro{font-size:12px;color:#737b8d;margin-bottom:12px}.rewrite-area{width:100%;min-height:500px;border:1px solid #e2e4ed;border-radius:11px;outline:0;resize:vertical;padding:15px 16px;font:15px/1.8 Georgia,"Times New Roman",serif;color:#2f3443;background:#fff;transition:.15s}.rewrite-area:focus{border-color:#b9baff;box-shadow:0 0 0 3px rgba(86,84,245,.08)}.rewrite-meta{display:flex;justify-content:space-between;gap:10px;margin-top:8px;font-size:11px;color:#9aa0ad}.word-meta.warn{color:#b45309;font-weight:700}.translate-row{margin-top:10px;display:flex;align-items:center;gap:8px}.translate-row .btn.link{font-size:11.5px;font-weight:760;padding:0}.orig-translate-row{margin-top:9px;padding-top:8px;border-top:1px dashed #e8eaf3}.orig-translate-row .btn.link{font-size:11.5px;font-weight:760;padding:0}.orig-translate-box{margin-top:8px;background:#fafbff;border:1px solid #e8eaf6;border-radius:10px;padding:9px 10px}.ot-line{font-size:12.5px;line-height:1.75;color:#4c5468;padding:6px 9px;border-left:3px solid transparent;border-radius:6px;margin-bottom:5px;background:#fff}.ot-line:last-child{margin-bottom:0}.ot-line[data-note-id]{cursor:pointer}.ot-line sup{font-family:Inter,"PingFang SC",sans-serif;font-size:8px;font-weight:800;color:var(--note-strong,#514ee1);margin-right:3px}.ot-line.note-rhetoric,.ot-line.note-repeat,.ot-line.note-growth,.ot-line.note-structure{border-left-color:var(--note-line);background:var(--note-soft)}.ot-line.note-rhetoric.active,.ot-line.note-repeat.active,.ot-line.note-growth.active,.ot-line.note-structure.active{background:var(--note-bg);box-shadow:0 0 0 2px color-mix(in srgb,var(--note-line) 28%,transparent)}.translate-box{display:none;margin-top:8px;background:#f6f7ff;border:1px dashed #d9dcf5;border-radius:10px;padding:11px 12px;font-size:12px;color:#4c5468;line-height:1.75;white-space:pre-wrap}.translate-box.open{display:block}.translate-label{font-size:10px;color:#8b92a3;font-weight:800;margin-bottom:5px;display:block}.rewrite-help{margin-top:16px;border-top:1px solid var(--line);padding-top:13px}.help-entry{display:flex;align-items:center;gap:8px;font-size:11.5px;color:#777e8f}.help-entry .btn.link{font-size:11.5px;font-weight:760;padding:0}.help-panel{display:none;margin-top:10px;background:#fafbff;border:1px solid #e6e7f3;border-radius:10px;padding:11px 12px}.help-panel.open{display:block}.help-label{font-size:10px;color:#8b92a3;font-weight:800;margin-bottom:5px}.scaffold{font-size:12px;color:#50586a;line-height:1.7;white-space:pre-wrap}.reference-trigger{margin-top:9px;padding-top:8px;border-top:1px solid #eceef4}.reference{display:none;margin-top:8px;background:#fff;border:1px solid #e6e7ef;border-radius:8px;padding:9px 10px;font-size:11.5px;color:#596174;white-space:pre-wrap;line-height:1.7}.reference.open{display:block}.reference-note{font-size:10px;color:#9198a7;margin-top:6px}.write-tools{border-top:1px solid var(--line);padding:11px 14px;display:flex;justify-content:space-between;gap:10px;align-items:center}.nav-group{display:flex;gap:8px}.demo-hint{font-size:11px;color:#9a9fac}
 .submit-row{position:fixed;left:0;right:0;bottom:0;background:linear-gradient(180deg,rgba(246,247,251,0),#f6f7fb 35%);padding:28px 24px 16px;display:flex;justify-content:flex-end;z-index:25;pointer-events:none}.submit-row .submit-inner{width:100%;max-width:1540px;margin:0 auto;display:flex;justify-content:flex-end;align-items:center;gap:12px;pointer-events:auto}.submit-hint{font-size:12px;color:#8a6270}.submit-row .btn{padding:11px 18px}.recheck-history{position:fixed;right:24px;bottom:82px;width:min(440px,calc(100vw - 32px));max-height:54vh;overflow-y:auto;background:#fff;border:1px solid var(--line);border-radius:13px;box-shadow:0 16px 40px rgba(28,31,45,.18);padding:12px 13px;z-index:30;display:none}.recheck-history.open{display:block}.rhi-title{font-size:12px;font-weight:800;color:#3a4053;margin-bottom:8px}.recheck-history-item{border:1px solid #ecedf4;border-radius:10px;padding:9px 10px;margin-bottom:8px}.recheck-history-item:last-child{margin-bottom:0}.rhi-head{display:flex;align-items:center;gap:7px;font-size:11px;color:#666e80}.rhi-badge{font-size:10.5px;padding:2px 7px;border-radius:999px;font-weight:800}.rhi-badge.ok{background:var(--good-soft);color:#167655}.rhi-badge.warn{background:var(--warn-soft);color:#8a5d10}.rhi-latest{font-size:10px;color:var(--brand);font-weight:800}.rhi-meta{font-size:10.5px;color:#9aa0ad;margin-top:4px}.rhi-goal{font-size:11.5px;color:#4c5468;line-height:1.65;margin-top:5px}.rhi-revision{margin-top:7px}
 .demo-panel{position:fixed;left:14px;bottom:14px;z-index:60}.demo-panel details{background:#fff;border:1px solid #dfe2ea;border-radius:10px;box-shadow:0 7px 20px rgba(23,27,42,.08);font-size:11px;color:#7d8495}.demo-panel summary{cursor:pointer;padding:7px 10px;font-weight:700;color:#666e80}.demo-panel .demo-body{padding:0 9px 9px;display:flex;gap:6px;flex-wrap:wrap;max-width:260px}
 .loading-card{padding:20px 22px}.loading-title{font-size:16px;font-weight:760;margin-bottom:10px}.loading-row{display:flex;align-items:center;gap:9px;padding:7px 0;color:#687084;font-size:12px}.spinner{width:17px;height:17px;border:2px solid #dfe1ff;border-top-color:var(--brand);border-radius:50%;animation:spin .8s linear infinite}.loading-dot{width:8px;height:8px;border-radius:50%;background:#d7dbe6}.loading-row.active{color:#4247c7;font-weight:650}.loading-row.active .loading-dot{background:var(--brand)}.loading-hint{color:#b9770b;font-size:12px;font-weight:600;margin-top:8px}@keyframes spin{to{transform:rotate(360deg)}}
@@ -263,6 +263,11 @@ let recheckHistory = [];
 // 时视为过期，需重新翻译（保证译文对应当前版本）。
 let translations = [];
 let translateOpen = [];
+// 体验优化：原文中文对照（逐句）缓存（按段下标）。rec.sentences = [{en,zh}]，
+// 句子由前端拆分（en 是原文精确文本），命中批注 evidence 的句子在对照里
+// 与原文同色 + 同序号，让「需要改写的那句」能直接找到中文。
+let origTranslations = [];
+let origTranslateOpen = [];
 let analysisVersion = 1;
 let helpState = {};
 let dirtyDuringRecheck = false;
@@ -381,6 +386,10 @@ function ensureParaState(){
   while(translateOpen.length<n) translateOpen.push(false);
   translations = translations.slice(0,n);
   translateOpen = translateOpen.slice(0,n);
+  while(origTranslations.length<n) origTranslations.push(null);
+  while(origTranslateOpen.length<n) origTranslateOpen.push(false);
+  origTranslations = origTranslations.slice(0,n);
+  origTranslateOpen = origTranslateOpen.slice(0,n);
 }
 function briefFor(pid){return (diagnosis&&diagnosis.paragraph_briefs||[]).find(b=>b.paragraph_id===pid)||null;}
 function patternsFor(pid){return (diagnosis&&diagnosis.patterns||[]).filter(p=>(p.affected_paragraphs||[]).includes(pid));}
@@ -463,7 +472,7 @@ function applyEditedEssay(){
   paragraphs = splitParagraphs(essayText);
   // 文书内容变化后，旧版本（改写后全文）失去参照，清空版本切换与复检历史/译文
   essayVersions = []; viewedVersion = null;
-  recheckHistory = []; translations = []; translateOpen = [];
+  recheckHistory = []; translations = []; translateOpen = []; origTranslations = []; origTranslateOpen = [];
   ensureParaState();
   closeEditor();
   renderEntryEssay();
@@ -475,7 +484,7 @@ function loadSample(){
   wordLimit = 650;
   paragraphs = SAMPLE_ESSAY.slice();
   essayVersions = []; viewedVersion = null;
-  recheckHistory = []; translations = []; translateOpen = [];
+  recheckHistory = []; translations = []; translateOpen = []; origTranslations = []; origTranslateOpen = [];
   ensureParaState();
   closeEditor();
   renderEntryEssay();
@@ -490,7 +499,8 @@ function persistNow(){
       current, originalView, revisionMode, revisionTarget,
       referencesShown, scaffoldsShown, currentRewriteVersion,
       lastRecheckSnapshot, lastRecheckResult, analysisVersion, agentStage,
-      chatLog, essayVersions, viewedVersion, recheckHistory, translations, translateOpen
+      chatLog, essayVersions, viewedVersion, recheckHistory, translations, translateOpen,
+      origTranslations, origTranslateOpen
     }));
     return true;
   }catch(e){ return false; }
@@ -550,6 +560,8 @@ function restoreSession(){
     recheckHistory = Array.isArray(s.recheckHistory) ? s.recheckHistory.slice(0,10) : [];
     translations = Array.isArray(s.translations) ? s.translations : [];
     translateOpen = Array.isArray(s.translateOpen) ? s.translateOpen : [];
+    origTranslations = Array.isArray(s.origTranslations) ? s.origTranslations : [];
+    origTranslateOpen = Array.isArray(s.origTranslateOpen) ? s.origTranslateOpen : [];
     ensureParaState();
     if(essayText !== SAMPLE_ESSAY.join('\n\n')) openEditor();
     else renderEntryEssay();
@@ -908,8 +920,9 @@ function renderAnnotatedText(text, annotations){
 }
 function bindAnnotationInteractions(wrap){
   const activate = id => {
-    wrap.querySelectorAll('.annotation-anchor,.annotation-card').forEach(el=>el.classList.remove('active'));
+    wrap.querySelectorAll('.annotation-anchor,.annotation-card,.ot-line').forEach(el=>el.classList.remove('active'));
     wrap.querySelectorAll(`.annotation-anchor[data-note-id="${id}"]`).forEach(el=>el.classList.add('active'));
+    wrap.querySelectorAll(`.ot-line[data-note-id="${id}"]`).forEach(el=>el.classList.add('active'));
     const card = wrap.querySelector(`.annotation-card[data-note-id="${id}"]`);
     if(card){ card.classList.add('active'); card.scrollIntoView({block:'nearest',behavior:'smooth'}); }
     track('annotation_anchor_opened', {paragraph_id: pidOf(current), annotation_id: id});
@@ -919,6 +932,9 @@ function bindAnnotationInteractions(wrap){
     el.onkeydown = e => { if(e.key==='Enter'||e.key===' '){ e.preventDefault(); activate(el.dataset.noteId); } };
   });
   wrap.querySelectorAll('.annotation-card').forEach(el=>el.onclick=e=>{ if(!e.target.closest('.why-toggle')) activate(el.dataset.noteId); });
+  // 原文中文对照（逐句）：对照行与批注同色同序号 —— 点击对照行可联动高亮原文句
+  wrap.querySelectorAll('[data-role="orig-translate"]').forEach(btn=>{ btn.onclick = toggleOrigTranslate; });
+  wrap.querySelectorAll('.ot-line[data-note-id]').forEach(el=>{ el.onclick = () => activate(el.dataset.noteId); });
   wrap.querySelectorAll('.why-toggle').forEach(btn=>btn.onclick=e=>{
     e.stopPropagation();
     const card = btn.closest('.annotation-card');
@@ -956,10 +972,15 @@ function renderFocusOriginal(wrap){
       <div class="direction-line action"><span class="direction-chip action">重写要做什么</span><div class="direction-text">${escapeHtml(fusedGoal(current))}</div></div>
       <div class="direction-line ai"><span class="direction-chip ai">AI味要注意</span><div class="direction-text">${escapeHtml(fusedAiFocus(current))}</div></div>
     </div>`;
+  const otRec = origTranslations[current];
+  const otFresh = otRec && otRec.text === String(paragraphs[current]||'').trim();
+  const otOpen = !!(otFresh && origTranslateOpen[current]);
   const paper = `
     <div class="annotated-paper">
       <div class="paper-title"><strong>原文</strong><span>${notes.length} 类重写提醒 · 颜色区分问题类型</span></div>
       <p class="annotated-copy">${renderAnnotatedText(paragraphs[current]||'', notes)}</p>
+      <div class="orig-translate-row"><button class="btn link" data-role="orig-translate">${otOpen ? '收起中文对照 ↑' : otFresh ? '查看原文中文对照 →' : '原文中文对照 →'}</button></div>
+      ${otOpen ? `<div class="orig-translate-box">${origTranslateLinesHtml(otRec)}</div>` : ''}
       <div class="annotation-list">${annotationCardsHtml(notes)}</div>
     </div>`;
   const visibleMeaning = `<div class="rewrite-direction">
@@ -1123,6 +1144,60 @@ async function toggleTranslate(){
   btn.disabled = false;
   renderTranslateBtn(); renderTranslateBox();
 }
+// 体验优化：原文中文对照（逐句）—— 顾问读英文吃力时，特别是被高亮标注
+// 「需要改写」的句子，需要它的中文意思才能判断怎么改。
+// 句子由前端拆分（en 为原文精确文本，服务端原样回填），命中批注 evidence 的
+// 句子在对照里与原文同色 + 同序号，可直接对上。
+function splitSentences(text){
+  const raw = String(text||'').trim();
+  if(!raw) return [];
+  const parts = raw.match(/[^.!?]+(?:[.!?]+["'”’]?|$)/g) || [raw];
+  return parts.map(s=>s.trim()).filter(Boolean);
+}
+function noteHitForSentence(sentence, notes){
+  const norm = s=>String(s||'').toLowerCase().replace(/\s+/g,' ').trim();
+  const target = norm(sentence);
+  for(let i=0;i<notes.length;i++){
+    for(const ev of (notes[i].evidence||[])){
+      const needle = norm(ev);
+      if(needle && target.includes(needle)) return {index:i, category: notes[i].category||'rhetoric'};
+    }
+  }
+  return null;
+}
+function origTranslateLinesHtml(rec){
+  const notes = annotationsFor(current);
+  return (rec.sentences||[]).map(s=>{
+    const hit = noteHitForSentence(s.en, notes);
+    return `<div class="ot-line${hit?` note-${escapeHtml(hit.category)}`:''}"${hit?` data-note-id="${hit.index}"`:''}>${hit?`<sup>${hit.index+1}</sup>`:''}<span class="ot-zh">${escapeHtml(s.zh)}</span></div>`;
+  }).join('');
+}
+async function toggleOrigTranslate(){
+  const i = current;
+  const text = String(paragraphs[i]||'').trim();
+  const rec = origTranslations[i];
+  const fresh = rec && rec.text === text;
+  if(fresh){
+    origTranslateOpen[i] = !origTranslateOpen[i];
+    persistNow(); renderOriginalPane();
+    return;
+  }
+  const sentences = splitSentences(text);
+  if(!sentences.length) return;
+  const btn = document.querySelector('[data-role="orig-translate"]');
+  if(btn){ btn.disabled = true; btn.textContent = '翻译中…'; }
+  try{
+    const resp = await postJSON('/api/translate',{sentences, paragraph_id: pidOf(i)});
+    origTranslations[i] = {text, sentences: resp.sentences||[]};
+    origTranslateOpen[i] = true;
+    track('original_translated', {paragraph_id: pidOf(i), sentences: sentences.length});
+    persistNow();
+  }catch(e){
+    if(btn){ btn.disabled = false; btn.textContent = '翻译失败，点击重试'; }
+    return;
+  }
+  renderOriginalPane();
+}
 function resetHelpPanels(){
   const key = pidOf(current);
   const st = helpState[key] || {scaffold:false, reference:false};

main.py

@@ -21,6 +21,7 @@ from prompts import (
     build_reference_prompt,
     build_scaffold_prompt,
     build_translate_prompt,
+    build_translate_sentences_prompt,
     normalize_diagnose_payload,
 )
 from schemas import (
@@ -36,6 +37,7 @@ from schemas import (
     RevisionTarget,
     ScaffoldRequest,
     ScaffoldResponse,
+    SentencePair,
     TranslateRequest,
     TranslateResponse,
 )
@@ -203,7 +205,12 @@ def reference(req: ReferenceRequest) -> ReferenceResponse:
 
 @app.post("/api/translate", response_model=TranslateResponse)
 def translate(req: TranslateRequest) -> TranslateResponse:
-    """体验优化：改写区「译成中文对照」——顾问自查改写后原意/细节是否保留。"""
+    """体验优化：中文对照翻译。
+    - text 整段模式：改写区「译成中文对照」（自查改写后原意/细节是否保留）
+    - sentences 逐句模式：原文区「原文中文对照」（前端拆分句子，逐句对位，
+      让「需要改写的高亮句」在中文对照里能同色找到）。"""
+    if req.sentences:
+        return _translate_sentences(req)
     if not req.text.strip():
         raise HTTPException(status_code=422, detail="没有可翻译的文本")
     system, user = build_translate_prompt(req.text)
@@ -217,6 +224,28 @@ def translate(req: TranslateRequest) -> TranslateResponse:
     return resp
 
 
+def _translate_sentences(req: TranslateRequest) -> TranslateResponse:
+    clean = [s for s in (x.strip() for x in req.sentences) if s]
+    if not clean:
+        raise HTTPException(status_code=422, detail="没有可翻译的句子")
+    system, user = build_translate_sentences_prompt(clean)
+    # 句子数量校验复用 _count_check：不一致自动重试一次（对位可靠性依赖等长同序）
+    data = run_json("翻译", system, user, check=_count_check(len(clean), "sentences"))
+    items = data.get("sentences") or []
+    pairs: list[SentencePair] = []
+    for i, en in enumerate(clean):
+        zh = ""
+        if i < len(items) and isinstance(items[i], dict):
+            value = items[i].get("zh")
+            if isinstance(value, list):  # 模型偶发把字符串字段返回成数组
+                value = "".join(str(x) for x in value)
+            zh = str(value or "").strip()
+        pairs.append(SentencePair(en=en, zh=zh))
+    if not any(p.zh for p in pairs):
+        raise HTTPException(status_code=502, detail="翻译结果为空，请重试")
+    return TranslateResponse(paragraph_id=req.paragraph_id, sentences=pairs)
+
+
 @app.get("/")
 def index() -> FileResponse:
     return FileResponse(HERE / "index.html", media_type="text/html")

prompts.py

@@ -322,6 +322,22 @@ def build_translate_prompt(text: str) -> tuple[str, str]:
     return system, user
 
 
+def build_translate_sentences_prompt(sentences: list[str]) -> tuple[str, str]:
+    """逐句中文对照（原文区）：句子由前端拆分，模型只负责逐句翻译，
+    数量与顺序必须一致 —— 前端据此把「需要改写的高亮句」在中文对照里同色对位。"""
+    numbered = "\n".join(f"{i + 1}. {s}" for i, s in enumerate(sentences))
+    system = """你是 Human Voice Rewrite 工作流的中文对照翻译器。
+
+用户给出的是一段英文文书的逐句拆分（编号）。要求：
+- 逐句翻译成自然中文，与输入一一对应：数量一致、顺序不变；每句只翻这一句，不合并、不遗漏。
+- 忠实优先：保留细节、语气与情绪强度；不润色、不省略、不补写原文没有的信息。
+- 不做评价、不建议、不加注释。
+- 只输出 JSON：{"sentences": [{"zh": ""}]}（按输入顺序，数量与输入完全一致）"""
+
+    user = f"英文句子：\n{numbered}\n\n请输出 JSON。"
+    return system, user
+
+
 def _as_text(value, sep="；") -> str:
     """模型偶发把字符串字段返回成数组（如 ai_focus 给了 1–3 类问题的列表，
     2026-08-21 用户实测 4 段全中）——统一规整为字符串，避免 pydantic

schemas.py

@@ -170,12 +170,21 @@ class ReferenceResponse(BaseModel):
 
 
 # ------------------------------------------------------- 体验优化：中文对照翻译
+class SentencePair(BaseModel):
+    en: str = ""  # 原文句子（前端拆分，服务端原样回填，保证高亮对位可靠）
+    zh: str = ""
+
+
 class TranslateRequest(BaseModel):
-    text: str = Field(min_length=1)
+    # 整段模式（改写稿翻译）：text 必填；
+    # 逐句模式（原文中文对照）：sentences 必填。二者取其一。
+    text: str = ""
+    sentences: list[str] = []
     # 段落上下文（可选）：帮助模型稳定语气，不参与翻译输出
     paragraph_id: str = ""
 
 
 class TranslateResponse(BaseModel):
     paragraph_id: str = ""
-    translation: str = ""
+    translation: str = ""  # 整段模式
+    sentences: list[SentencePair] = []  # 逐句模式（与请求句子等长、同序）

test_demo.py

@@ -530,6 +530,25 @@ def test_api_translate_coerces_list_translation():
     assert r.json()["translation"] == "第一句。第二句。"
 
 
+def test_api_translate_sentences_shape():
+    """原文中文对照（逐句）：en 原样回填、zh 按序对位 —— 前端据此做高亮对位。"""
+    payload = {"sentences": [{"zh": "第一句译文。"}, {"zh": "第二句译文。"}]}
+    r = api_client(payload).post(
+        "/api/translate", json={"sentences": ["One.", "Two."], "paragraph_id": "p1"}
+    )
+    assert r.status_code == 200
+    data = r.json()
+    assert [s["en"] for s in data["sentences"]] == ["One.", "Two."]
+    assert data["sentences"][1]["zh"] == "第二句译文。"
+
+
+def test_api_translate_sentences_blank_422():
+    r = api_client({"sentences": [{"zh": "x"}]}).post(
+        "/api/translate", json={"sentences": ["  ", ""]}
+    )
+    assert r.status_code == 422
+
+
 def test_api_translate_empty_translation_502():
     r = api_client({"translation": "   "}).post("/api/translate", json={"text": "Hello."})
     assert r.status_code == 502