由于氟利昂系列制冷剂对大气有破坏作用,故目前对R12制冷剂能起替代的制冷剂是() ["R22","NH3","R134a","H2O"]
对于家用电冰箱一般压缩机功率在()时,可采自然空气冷却方式进行冷却 ["100W","60W","200W","150W"]
目前中国移动的GSM系统采用的是以下哪种方式()。 ["A.FDMA","B.TDMA","C.CDMA","D.SDMA"]
某冰箱铭牌上标明为三星级冰箱,则该冰箱冷冻室的温度可达到()度 ["-6","-24","-18","-0"]
某台分体空调开机后制冷效果差,那么不可能是下面哪种情况() ["制冷剂泄漏","脏堵","冰堵","电源电压为110V"]
年轮和假年轮