--- What does the notice on the wall say?

--- ‘No person         take books out of the reading room; otherwise he would be fined.’

A．will

B．may

C．shall

D．Must

一些食物的近似pH如下：番茄4.0～4.4；苹果2.9～3.3；牛奶6.3～6.6；鸡蛋清7.6～8.0．则下列说法不正确的是（）

A．胃酸过多的人应少食苹果

B．番茄汁属酸性食品

C．牛奶和鸡蛋清均为碱性食品

D．苹果汁酸性比牛奶强