点头 in English:

I have a nodding acquaintance with him.

Please answer either by nodding or shaking your head.

You kept nodding off during that lecture, didn't you?

You were nodding off at times during my lecture.

Tom has a nodding acquaintance with Mary.

I didn't get much sleep last night so I was nodding off all day at work.

People communicate approval by nodding, by clapping their hands, by smiling or laughing.

For example in Bulgaria, shaking one's head means yes while nodding one's head means no.

You are nodding over your work.