touch on

The article touched on the main problem.

文章提到主要问题。

I want to touch briefly on another aspect of the problem.

我想简单下这个问题的另方面。

In his lecture on geology, he touched on the subject of climate.

他关于质学的报告中, 也涉问题。

He touched me on the arm.

他碰了下我的手臂。

Such actions touch on betrayal.

这种行为近乎背叛。