我跟他打招呼，他只点头，不说话。

Wǒ gēn tā dǎzhāohu, tā zhǐ diǎntóu, bú shuōhuà.

I greeted him; he only nodded and didn’t speak.

他听了以后点头笑了。

Tā tīng le yǐhòu diǎntóu xiào le.

After listening, he nodded and smiled.

老师问他，他点头说知道了。

Lǎoshī wèn tā, tā diǎntóu shuō zhīdào le.

The teacher asked him, and he nodded and said he understood.