You will have an accident if you don’t ______, for the road is icy.

When we visited Zhou Zhuang again ten years later, we found it changed so much that we could hardly ________ it.

—I’m still working on my project.—Oh, you’ll miss the deadline. Time is       .

In developed countries, farm workers _________ only a small section of the population. 

In the future, care for the environment will become very important as earth’s natural resources _____．