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.