Neither of us forgot about it.

　　我倆都沒忘記它。

　　I forgot to ask him for his address.

　　我忘記向他要地址。

　　I've completely forgotten her name.

　　我完全把她的名字給忘了。

　　I've forgotten where they live exactly.

　　我忘記了他們的確切住址。