（ ） we have all the materials ready, we should begin the new task at once.

The government cannot operate effectively （ ） it is free from such interference.

Air pollution is obviously one of the major _____ of city life.

The idea sounds very good, but will it work in_____?

We want the committee to （ ） the details of the plan.

（ ） you do, you should put your heart into it.

I appreciate （ ） the opportunity to study abroad two years ago.

—Shall we invite Tim? —No， it’s too late to invite any more people. _____， he hates parties， you know.

To learn Chinese cooking, you should practice _____.

We should （ ） our differences and discuss the things we have in common.

A good teacher must know how to （ ） his ideas.

Any student who_____his homework is unlikely to pass the examination.