nonplussed

1.The speaker was completely nonplussed by the question.

演讲者被这个问题完全难倒了。

2.Diane was nonplussed by such an odd question.

黛安被这样一个古怪问题给困惑住了。

3.I was completely nonplussed by his sudden appearance.

他突然出现使我大吃一惊。

4.The professor is never at a nonplus, and never perplexed by a problem.

那位教授从来不会感到困惑，也不会被任何问题所难倒。