The scientists are trying to ___ natural energy to decrease air pollution.
| A．make friends with | B．make full use of | C．make notes of | D．make into |
Many students listened to the lecture, but I wondered how much they ______.
| A．took out | B．took up | C．took off | D．took in |
I think that something has to be done to stop the air from being polluted, ______ ?
| A．doesn't it | B．don’t I | C．don't they | D．haven't they |
It has been reported that some government leaders ______ their authority and position to get illegal profits for themselves.
| A．overlook | B．employ | C．abandon | D．abuse |
Let's learn to use the problem we are facing ______ a stepping-stone to future success．
| A．to | B．for | C．as | D． by |
His novels sell best and have made him famous, but before that no one could have imagined how great a role he ______ in the literary world．
| A．had played | B．has played | C．is playing | D．was to play |