0 the situation in which a lot of things are happening or people are moving around -- 活跃；繁忙；热闹
1 the work of a group or organization to achieve an aim -- 行动；活动
2 something that is done for enjoyment, especially an organized event -- （尤指有组织的）娱乐活动
The house, usually bustling with activity, was strangely silent.
The house was a hive of activity on the day before the wedding.
After a sudden burst of activity, the team seemed to run out of energy again.
After weeks of frenetic activity, the job was finally finished.
Textbook writing can be an intellectually and financially rewarding activity.
