1、I forgot to ask him for his address.
我忘记向他要地址。
2、 I forgot my purse (= I did not remember to bring it) .
我忘了带钱包。
3、‘Hey, don't forget me (= don't leave without me) !’
“喂，走时别落下我！”
4、Aren't you forgetting something? (= I think you have forgotten to do sth)
你是不是忘了什么？