讨论时间

　　a proverb says: time is money. but in my opinion, time is even more precious than money. why? because when money is spent, we can earn it back. however, when time is gone, it will never return. this is the reason why we must value time.

　　it goes without saying that the time for our study and work is unusually limited. hence, even an hour is extremely precious. we should make full use of our time to do useful things.