Because of ______ high demand for Type AB blood, ______ supplies of it are usually limited．

A．the; the

B．/; /

C．/; the

D．a; the

心肌梗死时不升高的酶是（）

A.肌酸激酶同工酶

B.乳酸脱氢酶

C.肌酸激酶

D.谷草转氨酶

E.碱性磷酸酶