改写下列同义句，每空一词。

1. Study harder, or you won't catch up with others.

    ______ ______ ______ study harder, you ______ fall behind others.

2. My brother didn't go to work. He stayed at home, instead.

    My brother ______ at home ______ ______ ______ to work.

3. How do you like his idea?

    ______ do you ______ his idea?

4. She has a headache.

    She has ______ ______ ______ in her head. Her head hurts.

5. My mother bought me a bike as a birthday present.

    A bike ______ ______ ______ ______ by my mother as a birthday present.