If you say that you are flabbergasted, you are emphasizing that you are extremely surprised.
例句
Everybody was flabbergasted when I announced I was going to emigrate to Australia.我宣布要移民去澳大利亚时,所有人都惊呆了。
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"