catch sb. off guard

• 乘其不备, 使人措手不及

catch sb. off guard的用法和样例：

例句

1. I'm sorry I didn't recognize you. You caught me off guard.
   我没有认出来是你,我没太注意。
2. The pitfall is the trappings of success can catch you off guard.
   陷阱就是，成功的表象来袭时，你可能猝不及防。
3. His purpose is to catch us off guard.
   他的目的是想让我们失去警惕。