通读下面短文，掌握其大意, 然后在每小题所给的四个选项中选出一个最佳答案。

Someone says" Time is money", but I think time is much more important than1. Why? Because when there is no money, we can get it back. However, when time2, it will never come back. That is3we must not waste（浪费）time.

There is no need to tell anyone that time is4. Every second is very helpful. We should use our time to do5useful.

But it is a pity（可惜）that a lot of6do not know the importance of time. They spend their free time smoking, drinking and7. They do not know that wasting time means wasting part of their own8.

In a word, we should save time. We shouldn't9today's work for tomorrow. Remember we have no time to10. We should spend our time doing helpful things.