能反馈抑制自身分泌的胃液成分是（）
A.碳酸氢盐
B.内因子
C.盐酸
D.胃蛋白酶
E.黏液
参考答案：C
满载开关一般整定为额定载荷的（）时动作.
A.80％
B.90％
C.100％
D.110％
When deeply absorbed in work, _______he often was, he would forget all about eating or sleeping.
A．where
B．that
C．what
D．as
