美国药典信息开发部对药物适应症或禁忌症的信息分等为
A．1类
B．2类
C．3类
D．4类
E．5类
参考答案：E
Tiring as it might be, the military training ______ the best opportunity to make lifelong friends.
A．is believed to be
B．believes as
C．is believed to being
D．believes
