商业周期

例句：

1. 1. The business cycle is the period of economic activity in a country.
   商业周期是一个国家经济活动的时期。
2. 2. The economic cycle has been affected by the global pandemic.
   经济周期受到了全球大流行的影响。
3. 3. The business cycle is closely linked to the stock market.
   商业周期与股市紧密相关。