有机磷农药中毒的机制是（）

A.抑制单胺氧化酶

B.抑制磷酸二酯酶

C.抑制胆碱酯酶

D.抑制腺苷酸环化酶

E.直接激动胆碱受体

A survey of the opinions of experts ______ that three hours of outdoor exercise a week _____ good for one’s health.

A．show; are

B．shows; is

C．shoe; is

D．shows; are