慢性胃炎最主要的原因是
A．自身免疫B．十二指肠液反流C．幽门螺杆菌感染D．长期饮酒E．吸烟
参考答案：C
They are still very cautious about ______ side effect the new medicine will bring about, although the experts have tried it on about 2,000 patients.
A．which
B．that
C．where
D．what
单纯针对碳化度而言，反应区上移对（）有利，但是（）损失高。
A、转化率，二氧化碳
B、转化率，氨
C、沉降量，二氧化碳
D、沉降量，氨
