________ the question of how global warming has _________, we are doing some projects at school.
| A．Exploring, come about | B．To explore, come out |
| C．Having explored, come to | D．Being explored, come over |
It was said ____that was _____ he succeeded in running his business.
| A．that, what | B．that, that | C．what, how | D．that, how |
The farmers are only allowed to cut ______ trees and cut them _______ for firewood once a year.
| A．down, up | B．up, down | C．off, across | D．down, out |
Doctors say _____ good diet is of ______ great benefit to our health.
| A．a , a | B．the, a | C．a, / | D．the, / |
Mike is a student at a famous university, _______ for a doctor degree.
| A．studied | B．studying | C．to have studied | D．to be studying |
There is a feeling in me _______ we’ll surely find a cure for Aids.
| A．that | B．which | C．of which | D．when |