用糖皮质激素治疗休克的主要机制是()
A.疏通内循环,扩张小血管
B.稳定细胞膜和细胞器
C.阻断儿茶酚胺的有害作用
D.增强肝脏的解毒作用
E.增强心肌收缩力
参考答案:B
A: Your bicycle looks very nice. When did you buy it?
B: Oh, I ______ it for three months. It's a birthday present from my uncle. [ ]
A. bought
B. have bought
C. have received
D. have had
社会主义国家公安机关与剥削阶级国家警察机关所维护的阶级利益不同。 ( )