(一).(That's) Water under the bridge. 忘記發生過的事吧！

原音重現：
A:Weren't you angry with Bob last year?
去年你沒對鮑勃發過火嗎？
B:I was, but that's water under the bridge.
發是發過，但那是過去的事了。
英英釋義：
This is a way of saying "Let's forget about it." It is said to indicate something happened in the past and should be forgotten.
美劇表達：
1.Oh, it's water under the bridge. Forget it!
都是過去的事了，忘了吧！

(二).I seem to have lost track of it. 我好像已經忘記了。/好像已經記不得了。

原音重現：
A:Can I borrow your English dictionary.
能借你的英語詞典用一下嗎？
B:I'm not sure where it is. I seem to have lost track of it.
我不知道在哪兒，我忘記放哪兒了。
英英釋義：
This indicates something was forgotten or not kept in touch with. It is like saying "I don't remember where it is" or "I didn't stay in touch."
美劇表達：
1.I'm sorry. I guess I lost track of time.
對不起，我忘記時間了。