一碳单位的辅酶是( )
A．叶酸B．二氢叶酸C．四氢叶酸D．NADPHE．NADH
参考答案：C
—It’s important ________ us _______ learn English well.
—I agree with you. We should try our best to learn it.
A. to, to B. to, for C. for, to
人参皂苷三醇型是（）
A.I型强心苷
B.II型强心苷
C.III型强心苷
D.A型人参皂苷
E.B型人参皂苷
