选词填空 3 before, discover , fast, in, come, w atch , 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. " 选词填空 4 other, move, enough, find ,desert, make, use , another, friend , carry , trouble, friend You may think there is nothing but sand in the desert of the world, but it is not true. In the desert we can 1._______ stones. We can see hills, too. There is a little rain in the 2.________, but it is not 3. ______ for most plants. The animals are 4. _______ to the desert people in many ways. The desert people eat the meat and drink the milk of the animals. They use their skins to 5. ________ shoes, water bags and even tents(帐篷). They use the camels(骆驼) for 6. _______ things. The people of the desert hav...
