verbs 的用法

第1題要用加s
因為he,she,it後既present tense要加s
第2題要用won,感覺上
因為呢句似敍述,所以係過去既事件,所以用past tense
*當然,我都要知道你既上文下理係咪講past tense@@
第3題用decide,唔可以用decided
因為must作為modal verb既時候後面一定係present tense
如果你想講佢過去應該要決定
可以寫:
She must have decided what to do next.
咁樣就可以表示過去既意思,同埋佢有後悔既意思
*個人感覺咁樣寫比較似writer想表示既意思

1. He fights (fight) against her. (present simple tense)
2. But then one day, she won (win). (past simple tense)
3. She must decided (decide) what to do next. (Wrong)

The first two sentences are right.

Must is a modal auxiliary verb. Must goes before a main verb. It has no infinitive or participles, no past tense. Like other modal verbs, must has no -s on the third peson singular (he must, not *he musts) ; questions and negatives are made without do (Must I?) Must is follow by infinitive without to.

She must decide what to do next. (correct)

Must has no past tense. For the Past Simple, use "had to".
She had to decide what to do next.

Present Perfect:
They must have left early.

Present Continuous:
They must be working late.

In indirect speech, we can use must for describing something in the past.
I told her she must be careful.
I felt that thee must be something wrong.

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