1. my bicycle has been stolen 
2. unless he works hard, he will not pass his exam 
3. If I had free time, I could go some where
4. because Vy ate a lot last night, she had a stomachache
5. after I had got up, my mother went to work

1. My bicycle has been stolen

⇒ Câu bị động thì HTHT: has/have + been + V3/ed

__________

2. Unless he works hard, he won't pass his exam.

⇒ Câu điều kiện loại 1: If + S + V, S + will/can/may... + V

⇒ Unless = If not = nếu không

_____________

3. If I had free time, I could go somewhere.

⇒ Câu điều kiện loại 2: If + S + V2, S + would/could/might + V

___________

4. Because Vy ate a lot last night, she had a stomachache.

⇒ Because + clause = bởi vì ...

____________

5. After my mother had gone to work, I got up.

⇒ After + Thì QKHT, Thì QKĐ