association in time

例句：

1. 1. The two companies have formed a joint venture to promote their products.
   两家公司成立了合资企业以推广其产品。
2. 2. He joined the local community club last month.
   他上个月加入了当地的社区俱乐部。
3. 3. The scientists are working together to solve this complex problem.
   科学家们正在合作解决这个复杂的问题。