Question

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多途选项。

　　Laser(激光)is short for Light Amplification by Stimulated Emission of Radiation．Laser light is different from daylight or electric lights．Industry put lasers to work almost immediately after they were invented in nineteen sixty．　　1　　．

　　The first medical operation using a laser took place the year following its invention．Doctors Charles Campbell and Charles Koester used a laser to remove a tumor from a patient's eye at Columbia-Presbyterian Hospital in New York City．　　2　　．

　　Lasers have made measurement an exact science．Astronomers have used lasers to measure the moon's distance from Earth．　　3　　．For example, drawing a perfectly level straight line on a construction site is easy using a laser．

　　　　4　　．And the jewelry industry uses lasers to write on the surface of the world's hardest substance, diamonds．

　　Lasers are found in many products used almost everywhere．Over one hundred years ago, writers imagined that beams of light could be powerful weapons．Today, lasers guide missiles and bombs．American defense companies are working on giant laser guns recognizable to science fiction fans everywhere．　　5　　．

　　Scientific American magazine says huge lasers turn only about twenty to thirty percent of the energy they use into a laser beam．The rest is lost as heat．

　　That has not stopped scientists from working to perfect powerful lasers that, one day, may be able to shoot missiles out of the sky．

A．But weapons were not the first to use it on the list．

B．All lasers have several things in common．

C．Mappers and builders use laser technology every day．

D．But there are technological difficulties．

E．Lasers have also changed the way we communicate．

F．Manufacturers have used lasers for years to cut and join metal parts．

G．Since then, doctors have used lasers to cut and remove tissue safely with little risk of infections．

Answer 1

答案：
解析：

A　G　C　F　D