call on ...

phr

• ① 访问(某人)

• ② 要求(=ask);恳求(=appeal to)
  • She called on us for help.她要求我们帮助。
  • They called on him to support them.他们请求他去支持他们。
  • He was called on to make a speech.他被请求发表一篇演讲。

• ③ 需要使用(资源、体力等)(★可用被动式)
  • We should call on all our resources to modernize our industry.我们应该动用一切资源使我们的工业现代化。