顿然

tā bù dé bù gēn tā shuō huà shí yǒng qì dùn rán jìn shī

他不得不跟她说话时，勇气顿然尽失。

When he had to speak to her his courage suddenly deserted him.

tīng dào zhè huài xiāo xi tā dùn rán shī sè

听到这坏消息，她顿然失色。

She blanched to hear the bad news.