时/体回答”动作何时发生”，本篇处理动词系统的另外三个维度：voice（语态）调整主语与动作的语义关系，modality（情态）在事实之外表达推测与义务，subjunctive（虚拟语气）表达反事实与愿望。三者叠加在 动词与时态 的 16 格时体矩阵之上，构成英语动词的完整形态空间。
被动语态 Passive Voice
形式系统
被动 = be（承载时/体）+ past participle（过去分词，形态细节见 非谓语动词）。主动句宾语升为主语，原主语退居 by 短语或省略。
| 时/体 | 主动 | 被动 |
|---|---|---|
| 一般现在 | writes | is/are written |
| 一般过去 | wrote | was/were written |
| 现在完成 | has written | has/have been written |
| 过去完成 | had written | had been written |
| 进行体 | is writing | is/are being written |
| 将来 | will write | will be written |
| 将来完成 | will have written | will have been written |
| 情态 | must write | must be written |
注意两点：完成进行时与将来进行时几乎不用被动；进行被动只存在于现在/过去两个时点（is being done / was being done）。
get-passive
get + 过去分词是 be-passive 的口语变体：get hurt, get fired, get paid, get stuck。语用差异：
- 强调结果或意外，而非状态：He got fired 侧重事件降临，He was fired 侧重客观陈述
- 主语通常有某种”遭受或受益”的体验感，常暗示自身有责任（get involved）或运气不好（get caught）
- 少用于正式文体与学术写作
使用场景与滥用
被动语态的正当场景：
- 施动者未知或不重要：My car was stolen last night.
- 信息结构需要（end-focus）：把新信息或焦点推到句尾——The novel was written by a nineteen-year-old girl.（焦点在作者）
- 学术与公文文体：Methods section 惯用 The samples were heated to 80°C，回避人称
- 衔接需要：延续前句话题，保持主语一致
滥用信号：责任模糊（Mistakes were made 回避问责）、层层嵌套（It was decided that approval would be sought）、以及施动者其实关键却被藏起来。写作中除非有明确的信息结构理由，优先主动。
不能被动化的动词：不及物动词（happen, occur, arrive）、宾语为反身代词或同源宾语（she dreamed a dream）、状态动词（have, lack, resemble——cost, weigh 表属性时）。
情态动词 Modal Verbs
义务与推测两轴
每个情态动词都活跃在两条语义轴上：deontic（义务/许可/能力，指向行为）与 epistemic（推测，指向真值）。确定度从上到下递减：
| 情态动词 | 义务/许可轴 | 推测轴（肯定度） |
|---|---|---|
| must | 必须（强制） | 一定（≈95%） |
| can’t / couldn’t | 禁止 | 不可能（≈5%） |
| should / ought to | 应该（义务弱于 must） | 按理应该（≈70%） |
| may | 许可 | 可能（≈50%） |
| might / could | —（could 表过去能力） | 或许（≈30%） |
关键陷阱是否定不对称：
- You mustn’t tell her —— 禁止（不许说），不是”不必”
- You needn’t tell her —— 无义务（不必说）
- He can’t be home —— 推测否定（不可能在家）
- He may not be home —— 歧义：推测（可能不在）或拒绝许可（不可以待在家），靠语境消解
完成式情态：modal + have + done
完成式情态把情态投射到过去，是阅读与考试的核心考点：
| 形式 | 语义 | 例 |
|---|---|---|
| must have done | 对过去的强推测 | The ground is wet. It must have rained. |
| can’t have done | 对过去的强否定推测 | He can’t have finished so fast. |
| may/might have done | 对过去的弱推测 | She might have missed the train. |
| should have done | 本应做而未做（责备/遗憾） | You should have told me earlier. |
| needn’t have done | 本不必做却做了 | We needn’t have booked—the place was empty. |
| could have done | 本能够做而未做 | I could have sworn I locked the door. |
might have done 与 could have done 还可表未实现的可能（counterfactual 可能性），与虚拟语气交界。
情态动词的句法特性：第三人称单数不加 -s；疑问/否定直接倒装或加 not（无 do-support）；ought to 是唯一带 to 的核心情态词；间接引语中不后移（ yesterday he said he might come，may 不变 might 的规则不适用——因为已经是情态）。
虚拟语气 Subjunctive
三类 if 条件句
英语用时态后移（backshift）表达反事实：形式上往过去推一格，语义上与现实拉开距离。if 条件句属状语从句（从句体系见 三大从句）：
| 类型 | if 从句 | 主句 | 语义 |
|---|---|---|---|
| 真实条件 | if + 现在时 | will + 原形 | 可能实现 |
| 与现在事实相反 | if + 过去式（be → were） | would/could/might + 原形 | 反事实-现在 |
| 与过去事实相反 | if + had done | would/could/might have done | 反事实-过去 |
| 与将来可能性小 | if + should do / were to do | would + 原形 | 遥远假设 |
与过去相反的经典例：If I had known, I would have told you.（事实上不知道，也没告诉。）
Mixed Conditional
时间轴可以交叉：从句时间与主句时间不必一致。
- 过去条件 → 现在结果：If I had taken that job, I would be in Shanghai now.（过去的选择解释现在的处境）
- 现在条件 → 过去结果：If he weren’t so shy, he would have asked her out.（现在的性格解释过去的未行动）
判读方法：分别判定从句与主句各自指向的时间，再核对各自的动词形式，不要套模板。
触发 subjunctive 的句型
mandative subjunctive（命令虚拟）：suggest, demand, insist, require, order, propose, recommend, request 等动词，以及 It is essential/imperative/vital that 结构，that 从句谓语用动词原形（不带时态与一致标记）：
- I suggest that he apply for the position.（美式省 should 用原形；英式常作 should apply）
- It is imperative that every member send the form by Friday.
wish / if only（愿望，一律后移一步）：
- wish + 过去式：对现在的愿望（I wish I knew）
- wish + had done：对过去的遗憾（I wish I had studied harder）
- wish + would：对将来的不满/抱怨，暗含对他人行为的无奈（I wish you would stop smoking）
- if only 是 wish 的强化版，语气更感伤
同族结构：would rather + 过去式（I’d rather you left now）、as if / as though + 虚拟（He talks as if he owned the place）、it’s (high) time + 过去式（It’s time we left）。
倒装虚拟
if 可省略，条件句改为助动词提前的倒装（详见 倒装、强调与省略）：
- Were I you, I would take the offer.（← If I were you）
- Had he known the truth, he would have acted differently.（← If he had known）
- Should you need anything, call me.（← If you should need）
注意只有 were / had / should 三个词能这样提前；had 此处是助动词，不能拿实义动词冒险（Had he money ✗ → If he had money）。
三个维度的统一视角
被动调整论元与视角，情态调整真值承诺的强度，虚拟调整现实距离。三者常叠加：The report must have been submitted by now（情态推测 + 被动 + 完成式）；Had the sample been tested earlier, the flaw would have been caught（倒装虚拟 + 被动 + 过去反事实）。形态上它们都寄生在 be/have/情态词这套”功能动词”上——这正是英语分析语取向的体现。体系定位见 英语语法体系总览 与 语法 MOC。