1.be busy with sth 忙于某事
I'm busy with my homework.
My father is busy with his work now.
2.be busy doing sth 忙于做某事
She is busy doing housework.
My teacher is busy preparing the exam papers.
3.help sb do sth 帮助某人做某事
Why not help me clean the classroom?
You should help your parents clean the house.
4.thought about doing.考虑做某事
He thought about opening a private school in his hometown.
She thought about buying a gift for her boy friend.
5.decide to do.决定做某事
I decided to learn English well.
Have you decided to help me?
6.sb spend + 时间 doing sth 某人花费多少时间做某事
I spend two hours surfing on the Internet every day.
You should spend half an hour taking exercise every afternoon.