题目

I would appreciate ______ you could give me some advice on TOFEL test.    A. it if                B. it whether             C. that when         D. that if   答案：A用pH测定下列液体的pH，其中pH＞7的是 [　　] A．纯净水B．蔗糖溶液 C．胃液D．人体血液