Slipped my mind 我忘了
Eg 1: I’m sorry I forgot to respond to your email. It just slipped my mind. 很抱歉，忘记回复你的邮件了，把这事忘记了。
Eg 2: -Don’t you know what date is it today?
-Oh, it’s your birthday. It completely slipped my mind.
-你知道今天是什么日子吗？
-哦，是你的生日，我完全忘记了。
Be terrible with 不在行
Eg 1: You’re terrible with numbers. You can’t even remember your own telephone number. 你对数字不敏感，你连自己的电话号码都记不住。
Eg 2: I’m terrible with directions. I’m always getting lost. 我没有方向感，经常迷路。
Eg 3: I’m terrible with faces, I can never remember what people look like.
我脸盲，永远记不清别人长什么样。
