感到困惑

The difficult problem present by him entangle the conferee.

他所提出的题使与会人士感到。

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

那位教授从来不会感到，也不会被题所难倒。

He was still more perplexed, for this inconsequent smile made nothing clear.

他然更加感到，为这突如其来的一笑，使他感到莫名其妙。