---My grandfather was ill in hospital last week.

---________.

A．I don’t think so

B．Sorry, I’m afraid not

C．That’s a good idea

D．I’m sorry to hear that

胃酸缺乏最可靠的判断指标是（）

A.呕吐物无酸

B.空腹胃液中无游离盐酸

C.空腹胃液pH≥7.0

D.最大酸分泌量等于0

E.基础酸分泌量等于0