1Subjunctive: insist + that + S + base verb (虚拟语气)
2Subjunctive: recommend + that + S + base verb (虚拟语气)
3Subjunctive passive: demand + that + S + BE + past participle
4Subjunctive: request + that + S + base verb (虚拟语气)
5Subjunctive after impersonal 'it is + adj': it is essential/important/necessary + that + S + base V
6Mixed Conditional: if + had + pp, would + base V (past cause → present result)
7Mixed Conditional (reverse): if + past simple (general state) → would have + pp (past result)
8Reverse Mixed Conditional: if + past simple/were (present trait) → would have + pp (past result)
9Reverse mixed conditional with COULD HAVE: present trait → past missed possibility
10Negative inversion: Never + have + S + past participle
11Negative inversion: Rarely + has + S + past participle (passive)
12Not only ... but (also) inversion: Not only + aux + S + V, but S + also + V
13Negative inversion: Little + did + S + base V (past tense deduction/awareness)
14Negative inversion: Under no circumstances + modal + S + base V (passive allowed)
15Negative inversion: On no account + modal + S + base V (passive)
16Negative inversion: At no time + aux + S + V (passive past)
17Negative inversion: By no means + be + S + complement
18Cleft sentence with What: What + S + V + is/was + N
19Cleft with What: What + S + V + IS + plural noun (singular verb stays)
20Cleft with What: What + S + V + WAS + N (past tense, singular)
21Cleft with What: plural subject inside What-clause, singular verb outside
22Cleft sentence with What + is + gerund (V-ing)
23What-cleft with DO: What + S + does/do + is + BASE verb
24What-cleft with DOES: What + S + does + is + BASE verb (no "to")
25What-cleft with DID (past): What + S + did + was + BASE verb
26What-cleft with DO (plural): What + S + do + is + BASE verb
27What-cleft with DO (past): What + S + did + was + BASE verb
28Cleft with What: What + S + V + is + to-infinitive (singular verb regardless of plural subject inside)
29Cleft with What + plan + is + to-infinitive
30Cleft with What + hope + is + to-infinitive
31Cleft with What + want + is + to-infinitive (plural-feeling subject inside)
32Participle phrase as modifier: -ing form leads the clause
33Perfect participle: Having + past participle (earlier completed action)
34Past participle phrase (passive) as modifier: V-ed leads the clause
35Negative present participle phrase: Not + V-ing leads the clause
36Perfect participle: Having + past participle (earlier completed action before main verb)
37Participle phrase: subject after comma MUST be the implicit doer (avoid dangling modifier)
38Inversion: No sooner + had + S + pp + than + S + V
39Inversion: Hardly + had + S + pp + when + S + V
40Inversion: Scarcely + had + S + pp + when + S + V
41Inversion: No sooner + had + S + pp + THAN + S + V (fixed collocation)
42Inversion: Hardly + had + S + pp + WHEN + S + V (fixed collocation; aux matches subject)
43Inversion: No sooner + had + S + been + pp + than (passive past perfect with inversion)
44Reported speech backshift: said/told + past tense (need → needed)
45Reported speech backshift: present perfect → past perfect
46Reported yes/no question: asked + if/whether + S + V (no inversion, backshift)
47Reported wh-question: asked + wh-word + S + V (no inversion, backshift present→past)
48Reported speech backshift: will → would; pronoun I → she
49Reported speech backshift: must → had to (modal of obligation)
50Wish + past perfect (regret about the past)
51Wish + would (annoyance / want someone to change behavior)
52Wish + past simple (unreal present state)
53Wish + past perfect (regret about PAST decision)
54Wish + would (annoyance at SOMEONE ELSE'S present/recurring behavior)
55Perfect infinitive passive: seems + to have been + past participle
56Modal + perfect infinitive: must have + past participle (past deduction)
57Verb + perfect infinitive: claim / pretend / appear + to have + pp (past reference from present viewpoint)
58Modal + perfect infinitive: should have + pp (criticism about what DIDN'T happen in the past)
59Modal + perfect infinitive: can't have + pp (past impossibility / strong negative deduction)
60Modal + perfect infinitive PASSIVE: should + have + been + past participle
61Gerund subject: V-ing phrase = singular subject → singular verb (is, not are)
62Gerund subject: V-ing phrase takes singular verb (helps, not help)
63Two gerund subjects joined by AND → plural verb (are, not is)
64Gerund subject: V-ing phrase = singular subject → singular verb (requires, not require)
65Gerund subject: V-ing phrase = singular subject → singular verb (takes, not take)
66Gerund subject + plural noun inside → singular verb (keeps, not keep)
67Gerund subject + multiple plural nouns inside → still singular verb
68Two gerund subjects joined by AND → plural verb (keep, not keeps)