引起慢性胃炎的主要病因是
A.幽门螺杆菌感染B.自身免疫反应C.机械因素影响D.化学因素影响E.黏膜退变
参考答案:A
解析: 目前认为慢性胃炎约90%由幽门螺杆菌感染所引起。
What worried the child most was _____________ to visit his mother in the hospital. [ ]
A. to his being allowed
B. his not being allowed
C. not his being allowed
D. not his allowed
施涂于A级基材上的无机装饰涂料,可作为()装修材料使用。
A、A级
B、B1级
C、B2级
D、B3级