Time.

Recently, I found time was a cruel thing. Whatever man is, time alway goes on. Time won't stay and waiting for somebody. You can't use anything to exchange time. I think time is also a fair thing because even if you have a lot of money or you enjoy high reputation, time won't leave them more.

Today I found I hadn't enough time. I found I had a lot things to do in this semester. I had a lot works to do and I had something necessary to do. Time is money, time is life.