touch on

The article touched on the main problem.

到主要问题。

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

我想简单地谈一下个问题的另一方面。

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

他关于地质学的报告中, 也涉及气候问题。

He touched me on the arm.

他碰了一下我的手。

Such actions touch on betrayal.

种行为近乎背叛。