come   watch  shine   fast   its     

    Light travels at a speed(速度) which is about a million times(76)_______     than that of sound in one second, about 300,000 kilometers while sound travels only 340 meters. You can get some idea of this difference by(77)_____       the start of a running match. If you stand far away from the starter(发令员) , you can see smoke(78)_______      from his gun before the sound reaches your ears.

The fast speed of light produces some strange facts. The nearest star is so far away that light which you can see from it tonight started to travel to you four years ago at a speed of nearly two million kilometers every minute. The light from some of tonight’s started on (79)_________journey towards you even before you were born.

So, if we want to be honest, we can’t say, “The stars are shining brightly tonight.” We have to say, “The stars look nice. They were(80)______        four years ago but their light has just reached our earth.”

The sun can shine on only half the earth _________.
A. at one time        B. at any time　　C. at a time        D. at times

(改写) She has _ hair. (shine)