To one's surprise 是令某人惊讶的是...，
in surprise是一种震惊的状态，
be surprised to do是对某件事感到惊奇！
【造句】
1.To one's surprise, they said okay!
让我们吃惊的是，他们说可以。
2.Sue screamed, not loudly, more in surprise than terror
休尖叫起来，声音不大，吃惊多于恐惧。
3.You may be surprised to hear that you do not need to have any specific amount of money at all.
你也许会感到惊讶当听到你并不需要准备任何具体金额的钱。
