— Another cup of tea?

— No, thanks. I _______ be off. My mom is waiting for me at home .

A．can

B．must

C．may

D．should

下列各项，与大黄、芒硝同用，使其泻而不速的是（）。

A.枳实

B.厚朴

C.大枣

D.山药

E.甘草