wit

1.wit（诙谐、滑稽）是抽象名词，前面不可加a，也没有复数形式。

2.at his（或her等）wits' end（不知所措的）和at his（或her等）wit's end都可以用，但似乎at his（或her等）wits' end比较普通。后面可以接不定式，也可以接what和how等词。例如：I had searched unsuccessfully all summer and was at my wits'（或wit's）end to find the right school for my daughter. 和He was at his wits'（或wit's）end what to do. in his（或her等）wit（清醒的）和out of his（或her等）wit（发狂的）似乎不及in his（或her等）wits和out of his（或her等）wits普通。

下面每组里的两句意思相同：

• He has a nimble wit.
  He has nimble wits.
• He does not seem to have the wit to understand the situation.
  He does not seem to have the wits to understand the situation.