中重度支气管哮喘发作首选治疗药物是()
A.β受体激动剂
B.糖皮质激素
C.茶碱类
D.抗胆碱能类
E.抗过敏类
参考答案:B
IP首部中,协议域=17,代表该协议类型为:()。
A.ICMP协议
B.IGMP协议
C.TCP协议
D.UDP协议
— I hear your friend is visiting San Ya again. Is it the second time for him?
— Yes, and he will come for _____ time next spring.[ ]
A. a third
B. a second
C. the third