1. He fights (fight) against her.
2. But then one day, she won (win).
3. She must decided (decide) what to do next.
- 10 年前最愛解答
因為must作為modal verb既時候後面一定係present tense
She must have decided what to do next.
- GodfreyLv 710 年前
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.
They must have left early.
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.資料來源： English grammar and Usage - Leech