have to 和must的区别

have to 和must的区别

英语中must和have to是一对近义词，都表示“必须，不得不”，但它们之间也有细微差别。
must用以表示说话者命令或期待做成某事，没有时态和词形的变化。
I must go to the bank to get some money.
我得到银行去取些钱。
When you enter the building you must
show the guard your pass.
进入大楼时须向警卫出示通行证。
Cars
must not park in front of the entrance.
入口处不得停放汽车。
You mustn't open the oven door before the cake is ready.
饼未熟不得打开烤箱的门。

have to用于他人发出指令或操纵的情况下，侧重指说话人个人的责任或义务，有各种时态和词形的变化。
I have to type letters and answer the phone.
我又得用打字机打信, 又得接电话.。
He has to pass an examination
before he can start work.
他须考试及格, 才能开始工作。
Have we to make our own way to the conference?
我们必须亲自到那里去开会吗?
You don't have to knock just
walk in.
你不必敲门--进来就是了。

must 与 have to 都有"必须、应该"的意思。但二者有区别：

 1) must 侧重于个人意志和主观上的“必须”，have to 则侧重客观上的必须，可译为“不得不”。must 与 have to 经常可以互换使用。例如：

 i must/have to go to school now. 现在我必须上学了。

 2) must 可用来表示现在和将来的必须，无时态变化；have to 则有更多的时态变化。例如：

 he had to give up the plan. 他不得不放弃这个计划。

 i will have to buy a new pen. 我不得不买枝新笔。

 3) 变否定句时，must 只要直接在其后加 not，而 have to 既可变成 haven't to，也可变成 don't have to / doesn't have to。