1 Laser beams can be used to bore metals and other hard materials. A trim B melt C drill D slice 2 The cost of elections in the United States is borne by both the government and the private sector. A known B fought C exposed D assumed 3 Acknowledged as the main cause of hay fever the pollen of ragweed is very bothersome. A intriguing B annoying C potent D significant 4 They got in quite a brawl. A snit B fight C bally D littering 5 By providing legal representation, the American Civil Liberties Union works to defend citizens against breaches of their civil rights. A branches B exercises C perusals D violations 参考答案 CDBBD