"出国的中学生一年比一年多"英文怎么说?

(There are) more and more high school students go abroad each year

go abroad:

到国外去,出国

例句与用法:
1. How much does it cost to go abroad?
出国要多少钱？
2. He hasn't decided to go abroad.
他还没有决定到国外去。
3. We can't go abroad this year, so we'll have to content ourselves with a holiday in Shanghai.
今年我们不能出国，所以只能去上海度假了。
4. If I lose my job, I will/shall go abroad.
如果我失业了，我就出国。
5. To go abroad to study, you should at least master the language.
要到国外读书, 你最起码要掌握那种语言。

There are more and more middle school students that go abroad.

我觉得可以这样说啦～～
An increasing number of middle school students are likely to go abroad.
呵呵～～希望你满意哦～～

There are more and more middle school students going abroad.

More and more middle school students go abroad.