最易发生变异而发生流行的流感病毒是
A．甲型和丙型流感病毒
B．甲型和乙型流感病毒
C．甲型流感病毒
D．乙型流感病毒
E．丙型流感病毒
参考答案：C
— I'm going to have a summer holiday in Dalian.
— _____ [ ]
A. Have a good time.
B. No, it's bad.
C. That's all right.
病案
