二氧化氯活化器上使用的压力表为（）压力表.
参考答案：电接点
-- Can you persuade your brother to go with us?
--- No, he will never do ______ he is asked to.
A. whatever B whenever C. however D. whichever
药材粉末中不含有草酸钙结晶的中药是（）
A.龙胆
B.半夏
C.延胡索
D.赤芍
E.三棱
