下列传染病中，病后可获持久免疫力的有（）
A.麻疹
B.水痘
C.流行性腮腺炎
D.脊髓灰质炎
E.乙脑
参考答案：A, B, C, D, E
The prices _____ up all the time and no one knows when it will become stable. [ ]
A. had gone
B. have been going
C. have gone
D. had been going
公司经理对董事会负责，是公司的代理人，所以经理必定是公司的法定代表人。
