The kid is quick-witted.
这孩子反应很快。

Mother's words touched my slow-witted mind.
母亲的一番话打动了我一贯愚痴的心。

He's quick-witted and does things efficiently.
他脑子快，做事效率高。

Having being upsetted, he became a bit slow-witted.
他受了刺激，变得有些呆痴。

He is much appreciated by his boss, because he is quick witted when handling affairs.
他办事灵利，很受老板赏识。

Human brains are like bodies that becomes more flexible when it is used often. Otherwise it will become dim-witted.
人的大脑和肢体一样，多用则灵，不用则废。

Mrs. Tweedy, the vicious camp commandant, and her slow-witted, henpecked husband have shown her prisoners what happens to a hen who hasn't laid eggs: it becomes a chicken with its head cut off.
这个苦役拘禁地邪恶的总长顿笛太太以及她那愚笨、惧内的丈夫向她的囚犯们展示了母鸡不下蛋会有什么结果：剁下脑袋，变成鸡肉。