be expected to do 跟be expected to be 的区别其实就是 do 与 be 的区别。比较：

Each man is expected to do his duty. 人当各尽其责。

They were expected to do the impossible. 他们被指望去完成难以完成的任务。

He is expected to be the key witness at the trial. 他将成为审判的关键证人。

The new plant is expected to be online by September. 这家新工厂有望9月份前提供在线服务。