小剂量阿斯匹林防治血栓形成是由于:
A.抑制脂氧酶
B.可逆抑制血管壁环氧酶
C.不可逆抑制血小板环氧酶
D.抑制磷酯酶A2
E.可逆抑制血小板环氧酶
参考答案:C
—You ought to have called him yesterday.
—Yes,I know I .
A.ought to
B.have to
C.should have
D.must have
简述我国社会主义市场经济体系的特征。