有一读者问这样一个句子：
(1)You're forgetting the old saying: One is never too old to learn, in any case, you're not old at all.
forget不能作延续性动词用，为何在此用进行时态呢？
一般说来，静态动词如want, know, believe, forget, understand等，皆无进行时态。但如强调其一时的心理活动，它们就可用作动态动词，具有进行时式，再如：
(2)She finds that no one is believing her.
(3)I'm remembering it.
(4)— He's senile?
— There's a word that I'm never knowing the meaning of.
如有兴趣，请参阅拙著《英语时态》（开明出版社出版）编号2.9.23。
