She could have gone off with some friends.

　　她可能和几个朋友出去了。

　　This glass is cracked. Someone could have dropped it.

　　这个玻璃杯破了。可能是谁把它掉在地上了。

　　- The money has disappeared! Who could have taken it?

　　- Tom could have taken it; he was here alone yesterday.

　　钱不见了！会是谁拿走的呢？

　　可能是汤姆拿走的；昨天只有他一个人在这儿。