When you feel like you're forgetting everything, when you feel like in this one situation, your vocabulary was amazing, your grammar was amazing, but in a different situation on a different day, you stumbled, you made a lot of mistakes, and now you are questioning your fluency.
當你覺得自己什麼都忘了的時候,當你覺得在這種情況下,你的詞彙量很驚人,文法也很驚人,但在另一天的另一種情況下,你卻磕磕絆絆,犯了很多錯誤,現在你對自己的流利程度產生了懷疑。