兼有抗组胺作用的镇咳药是
A．喷托维林
B．可待因
C．右美沙芬
D．苯佐那酯
E．氯哌斯汀
参考答案：E
It is the first time I _____ visitors since I moved to London.[ ]
A. had had
B. have had
C. have
D. had
需求分析中开发人员要从用户那里了解
A．软件做什么
B．用户使用界面
C．输入的信息
D．软件的规模
