93. They spent several years building this railway. (改写句子,句意不变)

　　 　　　　　　　　　　　　　　　　　　　　　several years to build this railway

92. I went to bed at eleven last night.(对划线部分提问)

　 　　　　　　　　　　　　　　　　　　　　　　you go to bed last night?

91. The students are in the classroom now. (改为否定句)

The students 　　　　　　　in the classroom now.

50. Could you tell me　　　 ? I want to post a letter.

A. how can I get to the hospital　　 　　　　　　B. how I can get to the cinema

C. where the post office is 　　　　　　　　　　D. where is the science museum