She could have gone off with some friends.

　　她可能和幾個朋友出去了。

　　This glass is cracked. Someone could have dropped it.

　　這個玻璃杯破了。可能是誰把它掉在地上了。

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

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

　　錢不見了！會是誰拿走的呢？

　　可能是湯姆拿走的；昨天只有他一個人在這兒。