（初二英语）同义词转换Why does he keep laughing?Why is he laughing ____

（初二英语）同义词转换
Why does he keep laughing?
Why is he laughing ____ _____ ____
If you clean your room every day,it will be good for your health.
_____ your room every day,_____it will be good for your health.
He decides that he will return to his hometown some day.
He ______ ______ ______ to him hometown some day.
People all over the world come to this beautiful city.
People _____ _____ ____ come to this beautiful city.