before, discover , fast, in, come, watch , so, fast it, ago , shine, not can
Light travels at a speed(速度) which is about a million times 1 . ________ than that of sound.  2. ________ one second, light travels about 300,000 kilometers, but sound travels only 340 meters. You can get some idea of this difference by  3. ________  the start of a running match. If you stand far away from the starter(发令员), you can see smoke 4.________ from his gun 5.________ the sound reaches your ears.
The fast speed of light produces some strange facts. The nearest star is 6. ________ far away that light which you can see from it tonight started to travel to you  four years  7. ________ at a speed of nearly two million kilometers every minute. The light from some of tonight’s started on 8. ________ journey towards you even before you were born.
So, if we want to be honest(诚实), we 9.  ________ say , " The stars are shining brightly tonight."  We have to say, " The stars look nice. They were 10. ________ four years ago but their light has just reached our earth. "
参考答案：
1.faster
2.In
3.watching
4.come
5.before
6.so
7.ago
8.its
9.cannot
10.shining