对过敏性哮喘有效的药物是（）
A.白三烯调节剂
B.色甘酸钠
C.钙拮抗药
D.酮替芬
E.血栓烷A
参考答案：D
若正比例函数y=kx（k为常数，且k≠0）的函数值y随着x的增大而减小，则k的值可以是______．（写出一个即可）
Dr. Smith, together with his wife and daughters, _____visit Beijing this summer.
A．is going to
B．are going to
C．was going to
D．were going to
