_____ , he doesn't study well. [ ]

A. As he is clever

B. He is as clever

C. Clever as he is

D. As clever he is

维生素K的止血作用是由于其能（）

A.促进血小板生成

B.增强毛细血管抵抗力

C.参与凝血酶的合成

D.抗纤维蛋白溶解