rewrite:
1/ we are lost now because you forgot to bring a map
-> If... you hadn't forgot to bring a map, we wouldn't be lost now
2/ I am not in the habit of staying up late at weekends.
-> I am not used... to staying up late at weekends ( tobe used to ving: quen với điều gì )
3/ If i were you, i would look for another job.
-> I think you... should look for another job
4/ If anyone knocks at the door, do not answer it.
-> Should... anyone knock at the door, do  not answer it 
5/ They reported that many children were homeless.
-> It.... is reported that may children were homeless
-> Many children... are reported to be homeless

1. If you hadn't forgotten to bring a map, we wouldn't be lost now.
2. I am not used to staying up late at weekends.
3. I think you should look for another job.
4. Should anyone knock at the door, do not answer it.
5. It is reported that may children were homeless.
    Many children are reported to be homeless.

Chúc bạn học tốt!