about和on的用法区别

例句：

It's about this high.

大约有这么高。

There was much discussion about the reasons for the failure.

就失败的原因进行了大量的讨论。

The population is increasing at about 6% per year.

人口以每年约6%的速度增加。

I got to know David on the second day of middle school.

我在上中学的`第二天就认识了大卫。

In our company, quality is high on the agenda.

我们公司高度重视质量。

The university is on the left bank of the river.

大学在河的左岸。