这个问题出乎意料，她一时语塞。

The question was unexpected and she was temporarily ___at ___a ___loss ___for ___words.

面对这样的善意，我完全不知道该说什么好。

Faced with such kindness, I was completely ___at ___a ___loss ___for ___words.

这个突如其来的消息让他完全说不出话来。

The sudden news left him utterly ___at ___a ___loss ___for ___words.