have to ,时态,Must,it is/was neccesary to doit was necessary for him to go out last night看了很多不同出版社的参考书答案都是 i've had to go out last night请问1.怎么理解这个答案,不是for him 怎么答案变成了i 做主

have to,must时态的差别．时态上有什么区别have to不能和什么时态一起? 时态转换It is______(excite)to have a picnic must／have to造句 must have to区别 she knew that it must be the baker 为什么不是she knew that it must have been the baker另：宾语从句什么时候要改时态? I must go now.It's late.为什么用must而不用have to? must,have to,have got Do you have to finish it tiday?这里have to可以换成must或者need吗? You must have missed it have been to是什么时态? it must be teenagers ___ fun.A.have B.having C.had D.to have she must have been a temporary worker 是什么时态?there has been a tendency to romanticize the accomplishments 是什么时态?是there be 为什么中间有个has? 英语语法时态 I thought you must have known that I ____ (be) happy when you ____ (say) con...英语语法时态 I thought you must have known that I ____ (be) happy when you ____ (say) congratulations to me! he was believed to have stolen it 为什么有was,believed是怎么回事,是什么时态 it's wonderful to have four seasons有什么时态语法方面的知识吗? Remember to put back the book,when you have finished it,从句为什么用完成时态 it's wonderful to have friends visiting from afar是什么时态! it's wonderful to have friends visiting from afar是什么时态!