例句：

　　1. Three years ago he clerked in a bank.

　　三年前他在一家銀行里當(dāng)職員。

　　2. She ticked off three items on the list.

　　她用記號標出表格上的三個項目。

　　3. I had only danced with Mary about three minutes when someone cut in.

　　我和瑪麗剛剛跳了大約三分鐘的舞，就有人來截舞。