为什么不能用must to be?

为什么不能用must to be? you must learn to be one .You must learn to treat your friend the way you want your friend to treat you一句中 the way 后面为什么不能用which who is that?it must be Mary.为什么不能用she? 半助动词 be bound to He must be in the office.=He is bound to be in the office .为什么?能用be sure to That's must be a mistike No,it can't be a mistike.中为什么不能用need't? The next thing ( ) must be done is to make a planA.which B.that C.when D./我能明白能用that但不能用which,但是为什么不能选择D呢? -I think the man over there must be Bob.-It ____ be him.He has gone to Australia.空格处为什么要用can't,不能用mustn't 1.The order came that the medical supplies (be sent) to Beijing for the H1N1 flu soon.为什么不能用 must be sent?2.Considering his ability,he (might have done) better.为什么不能用 could have done?3.Liza (may) well noe wang to go on the tri I am going to be a reacher,为什么一定要用be,不能用do? taking a boat to school___a lot more fun than taking a bus为什么填must have 不填must be there seem to be no need to ask the reason for it 为什么不能用it只能用there? 翻译一个英语句子Then we must use our self-control to be free of themThen we must use our self-control to be free of them翻译下这个句子并说明,这里的use为什么不能用help或ask谢谢 Marie _____a restless person. she kept moving from country to countryA must be B must have been 答案为B 我只知道must have been用表示对过去的推测 怎么这句陈述的话也用呢A为什么不能用呢 求解释谢谢 35.He must be from Africa,__________ can be seen from his skin.A.that B.as C.who D.what 答案是B为什么不能用C -____it be Peter who broke the vase?-No.It must be John who did it.为什么不能填Maymay不能用在问句里表推测么？ 新概念2的17课中She must appear in a bright red dress and long black stockings.为什么用must而不能用has to? 邀请函中有一句:we would be looking forword to your coming!上句中为什么要用would be?不能用will be 英语there used to be 是过去常有的意思为什么不能用 there are used to be 呢