I must have lost them probably about half way through

i must have lost my key~不用have行不? I must have lost them probably about half way through I have lost the library's book,and I must pay for it .为什么must和pay for 之间不加TO呢?俩个动词在一起了.. You must pay for the library book if you____itA lost B have lost Cwill lose Dhad lost I can't find the key to my office,I( )have lost it on my way homeA would B should C must D ought to have I found the lost child 还是 have I find the lost child The police still have I found the lost child,but they’re doing all they .A.can B.may C.must D.should (四川 20’)这题选 A 我明白.但是题干中警察让我找孩子为什么用 完形填空He must have been compietely lost in something he was reading because I had to tap on the I have get lost in the world of love.翻译 I have lost myself in the past days怎么翻译? I think i have lost They must have lost your letter in the post 怎么变被动语态 You letter must have been lost by them in the post. 的汉语是什么? He can't find his key.He ---------- them.A.must lost B.must have been lost C.must have lost 把We must sell allthese goods.they must have lost your letter in the post.改为被动语态. 把We must sell allthese goods.they must have lost your letter in the post.改为被动语态. they must have lost your letter in the post.They must have lost your letter in the post改被动语态your letter must have been lost by them in the post 1、有MUST的是什么时态.2、MUST后不是直接跟动词原型吗. I must have left the camera in the shop. i must have left the keys in the cofe.