特布他林平喘的主要机制是()
A.激动肾上腺素β2受体
B.抑制白三烯受体
C.阻断腺苷受体
D.拮抗M胆碱受体
E.抑制致炎物质的释放
参考答案:A
“What you want, you ____ have it on condition that you get the best result,” said the boss.
A.would
B.ought to
C.could
D.shall
初次点燃沼气灯新纱罩时,应将沼气压力适当提高,以便将纱罩吹鼓,便于工具将纱罩整圆。