These three characters all have the mouth radical (口 kǒu) on the left.
These are rarely used on their own; they usually have objects:
吃饭 chī fàn literally 'eat rice', but actually just 'eat'
喝水 hē shuǐ 'drink water'
唱歌 chàng gē literally 'sing a song', but actually just 'sing'