If you are dumbfounded, you are extremely surprised by something.
例句
I stood there dumbfounded.我站在那儿目瞪口呆。
英汉词典释义
adj.
惊呆的;目瞪口呆的
She was dumbfounded by the terrible news.她被这可怕的消息惊呆了。
英英词典释义
Adjective
1. as if struck dumb with astonishment and surprise;
"a circle of policement stood dumbfounded by her denial of having seen the accident""the flabbergasted aldermen were speechless""was thunderstruck by the news of his promotion"