同义句转换

同义句转换
1.Why does he keep laughing?
Why is he laughing ___ ___ ___.
2.If you don'twater the flowers,they will die.
_____ the flowers,____ they will die.
3.He decides that he will return to his hometown some day.
He ____ ____ ____ to his hometown some day.
4.People all over the world come to this beautiful city.
People ___ ___ ___ come to this beautiful city.