It was a period of intense activity.
Economic activity often follows a cyclical pattern.
经济活动常常遵循周期性模式。
He watched for signs of activity in the house.
他注视着那所房子里的动静。
The whole place was a scene of feverish activity.
整个地方都是一片紧张匆忙的景象。
He watched the house for signs of activity.
他注视着那所房子里的动静。
