特布他林的抗喘作用机制是
A．稳定肥大细胞膜B．阻断M受体C．抗炎、增加β2受体数量D．选择性激动β2受体E．促进肾上腺素释放
参考答案：D
出票人签发空头支票，银行应予以退票、并按票面金额处以50％但不低于1000元的罚款。()
A．正确
B．错误
Mary wrote an article on________ the team had failed to win the game. [ ]
A. why
B. what
C. who
D. that
