单词讲解：
premium n. 保险费，额外费用；奖金
premium rate 保险费率
短语讲解：
1. just a second= wait a miunte 请稍等
2. validity term= term of validity 有效期
3. up to 直到；在于……；能胜任
eg. When you sew up to this end, fasten off the thread.
当你缝到这头时，把线打个结。
eg. We saw a truck drawing up to our building.
我们看到一辆卡车开到我们楼前停住。
eg. I can take up to four people in my car.
我的汽车最多能坐四个人。
