急性胃炎的病因有
A．急性感染
B．急性应激
C．胆汁反流
D．药物刺激
E．以上均是
参考答案：E
Please ______ the lights before you leave the classroom. [ ]
A. turn down
B. turn on
C. turn off
D. turn up
监销人的职责：
