1. activity可以作为主语，其后可以加上动词来构成完整的句子。
- Activity is important for maintaining a healthy lifestyle. (活动对于保持健康的生活方式很重要。)
2. activity可以作为宾语，介词后面搭配动词或动名词形式。
- We enjoy outdoor activities in the summer. (我们喜欢夏天进行户外活动。)
- She spends her weekends engaging in creative activities. (她在周末参与创意活动。)
3. activity可以作为形容词，修饰名词。
- The activity room is filled with toys and games. (活动室里摆满了玩具和游戏。)
4. activity可以作为非谓语动词，与主句的主语保持一致。
- The children love to engage in outdoor activities. (孩子们喜欢参与户外活动。)
5. activity可以作为复数形式，表示多个不同的活动。
- There are various activities planned for the school event. (学校活动中有多种活动计划。)
