缓解哮喘急性症状的首选药物是（）
A、静脉用糖皮质激素D
吸入型速效β2受体激动剂(沙丁胺醇、特步他林)，吸入后1～5min起效，作用维持4～6h，是缓解哮喘急性症状的首选药物。
Thesmallmountainvillagewas（）bythesnowformorethanonemonth.
Mymotherwasdeterminedtohelpthoseinneedandshewouldhavebeenimmenselyproudofwhathasbeenachievedtheselast20years.Theitalicizedpartinthesentenceexpresses_______.
Toobtainasatisfactoryresult，onemustapplytwo____ofpaintonacleansurface.
Itwasrecommendedthatpassengers_____smokeduringtheflight.
Theopeningceremonyisagreatoccasion.Itisessential_____forthat.
