形容词
1. He is certain to come.
他一定会来的。
2. The evidence is certain and the facts are clear.
证据确凿，事实清楚。
3. I was certain that he had seen me.
我肯定他已看见了我。
4. A certain person called on you yesterday.
昨天有个人来拜访过你。
5. It is certain that two and two makes four.
二加二等于四是确定无疑的。