We are warned by our teachers not to waste time because time 21 will never return. I think it quite 22. What does time look 23? Nobody knows, and we can’t see it or touch it and no 24 of money can buy it. Time is abstract(抽象的), so we have to  25about it.
Time passes very quickly. Some students say they don’t have 26time to review their lessons. It is 27 they don’t know how to make use of their time. They waste it in going to theatres or playing, and 28 other useless things. Why do we study everyday? Why do we work? Why do most people 29 take buses instead of walking? The answer is very 30 .We wish to save time because time is31.
Today we are living in the 21^st century. We 32 time as life. When a person dies, his life ends. Since life is short, we must 33 our time and energy to our study so that we 34 be able to work and live well in the future. Laziness is the 35 of time, for it not only brings us 36, but also does other 37 to us. If it is necessary for us to do our work today, 38 us do it today and not 39 it until tomorrow. Remember that time is much more 40.

A．lost B．passed C．missed D．used

A．important B．true C．interesting D．usual

A．for B．like C．after D．over

A．amount B．quality C．quantity D．price

A．think B．imagine C．examine D．check

A．spare B．free C．enough D．much

A．that B．why C．because D．certain

A．doing B．making C．taking D．getting

A．needn’t B．have to C．had better D．would rather

A．easy B．simple C．stupid D．interesting

A．worthless B．priceless C．ready D．little

A．look upon B．agree C．think D．believe

A．spend B．give C．set D．devote

A．must B．should C．may D．would

A．helper B．thief C．friend D．teacher

A．wealth B．health C．failure D．illness

A．danger B．harm C．trouble D．difficulty

A．help B．make C．have D．let

A．keep B．remain C．manage D．leave

A．valuable B．expensive C．worth D．rich