肝素抗凝作用机制是
A．维生素K拮抗剂
B．抑制血小板功能
C．激活和强化抗凝血酶Ⅲ
D．激活纤溶酶原
参考答案：C
Ten years ago the population of our village was _______ that of theirs.
A．as twice large as
B．twice as large as
C．twice as much as
D．as twice much as
3级导流建筑物洪水标准，对混凝土材质导流建筑物洪水重现期为（）年。
A.5～3
B.10～5
C.20～10
D.50～20
