1 . He is a teacher but his wife is a doctor， ________？

A．isn’t she	B．isn’t it
C．aren’t they	D．isn’t he

2 . Mrs. Black doesn’t believe that her son is able to design a digital camera, ______?

A．is he

B．isn’t he

C．doesn’t she

D．does she

3 . ______ label to each of the trees, with detailed introduction of their features, and visitors will know more about them and how to protect them.

A．To attach

B．Attach

C．Attached

D．Having attached