根据句意从方框中选择合适的动词，并用其适当形式填空，使句子通顺。
| chat fly swim not be have |
1. Simon ___________ happy because he doesn’t do well in English.
2. Many young people enjoy _________ with each other on Wechat(微信).
3. Sandy often ______ kites with her friends at weekends.
4. Some children don’t know how _____________ fun.
5. Millie usually practises ____________ in the river in summer.
1. isn’t 2. chatting 3. flies 4. to have 5. swimming