Question

As we came to the work site, the workers were seen _______the new house.

A．building

B．build

C．built

D．to build

Answer 1

A

考查非谓语动词。本题考查see sb doing结构，用其被动语态即为sb be seen doing。句意：当我们来到工地的时候，我们看到工人正在建新房子。