To save people's lives,the doctors and scientists are risking their lives to do (医学的)research.
Our teachers often encourage us to face the difficulties (勇敢地) and try to overcome them.
When we are in danger, it's very important to make a good (决定).
Make sure there are no (错误) in your test paper before handing it in.
Our head teacher always (鼓励) us to solve problems by ourselves.
There is a train in now. If you run, you'll just (赶上) it.
The job was so (枯燥) that the young man finally left.
(青少年) are supposed to help with housework to develop their independence.
Prepare yourself for everything (在前面) of time, and you will be successful.
Doing sports can make people happier, (健康), and more confident.
Flying in the sky, we can see the fascinating city (在下面).
In the face of danger, all the firefighters were brave and (没有一个) of them gave up.