1 . She and her family hid away for nearly twenty-five months ___________. （discover）
她和她的家人躲藏了两年多之后才被发现。

2 . If Newton lived today, he would be surprise by what ____ in science and technology.

A．had discovered	B．had been discovered
C．has discovered	D．has been discovered

3 . The monument was built in honor of the explorer who was believed _____ the river.

A．to have discovered	B．to have been discovered
C．to discover	D．having been discovered