有几道英语题，向各位大师求助。。。帮个忙指导一下。

1.Lucy hasn‘t decided which trousers to buy.（改为复合句）
Lucy hasn't decided which trousers she should buy.
你给的这个第一个句话本身就是which引导的宾语从句，只不过是宾语从句的省略，wh疑问词+ to do 的形式，
2.I hope to see you again.（改为复合句）
I hope that i can see you again
3.从我家骑车到颐和园要用50分钟。
It usually __takes____ me 50 minutes ____to__ ___go___ __to____ the Summer Palace by bike from my home.

trousers which are to
someday when i
takes to go to

1·that which trousers to 这个是宾语从句和定语从句的结合
2.that I can 宾语从句
3.takes to go to 这是固定句型 ：It takes sb sometime to do sth