We need clear air and water, so we _____ protect the environment.
A. can B. may C. must D. might
He spent a lot of time on English. ______, he got the most points in the English test.
A. In fact B. Otherwise C. As a result D. However
______there is no buying, there will be no killing.
A. If B. While C. Because D. Since
Wolves have good team work. They usually work _____a team when they hunt.
A. for B. as C. of D. in
The environment here becomes better and better. ______ birds are coming back.
A. Thousands of B. Thousand of
C. Thousands D. Thousand
—Don’t be angry with your kid when he makes a mistake again, will you?
—No, I won’t. I know that _______ of us are perfect after all.
A. each B. either C. none D. all
