用must或have to来代替括号里的词组

Question

1.（It will be necessary for you to)see a doctor.
2.(Is it necessary for you to)make so much noise?
3.She said (it would be necessary for us to)stay here.
4.(It is necessary for me to)have some help.
5.(It was necessary for him to) go out last night.

Answer 1

1.You must see a doctor. (或 You will have to see a doctor.)
2.Must you make so much noise?
3.She said we have to stay here.
4.I must have some help.
5.He had to go out last night.
注：二者的区别在于：
1）must多表示主观性，而have to表示客观不得不做的，不论自己是否愿意都无法左右的。
2）have to可用于多种时态，有had to,will have to,would have to等多种变化，而must只能用作原形。所以当表示过去时的时候，只能用had to而不用must.

Answer 2

我只能告诉你must是表主观,have to表客观.
如It is late,I must go(主要是
你自己想走)
It is late,I have to go(主要是late的缘故你不得不要走)

Answer 3

1 you have to see a doctor.
2 do u have to make so much noise?
3 she said we must stay here.
4 i have to have some help.
5 he had to go out last night.

Answer 4

1.must
2.must
3.have to
4.must
5.have to