1.People have seen wolves in the streets.(变为被动语态)
2.people are demolishing many slums to make way for new buildings.(变为被动语态)
3.As I haven't watch ,I can't tell you the time.(改为虚拟语气)
4.They heard the boy make a phone call just now.(变为被动语态)
5.It is difficult to answer your question. The question is how I did it.(用同位语从句合并句子)

1.People have seen wolves in the streets.(变为被动语态)

wolves have been seen in the streets by people.
2.people are demolishing many slums to make way for new buildings.(变为被动语态)
many slums are being demolished to make way for new buildings by people
3.As I haven't watch ,I can't tell you the time.(改为虚拟语气)
if i had a watch, i could tell you the time
4.They heard the boy make a phone call just now.(变为被动语态)
the boy was heard to make a phone call just now.
5.It is difficult to answer your question. The question is how I did it.(用同位语从句合并句子)
it is difficult to answer your question how i did it


参考文献： 个人见解