患者，男，40岁。雪天骑车外出，右下肢骨折，已用石膏绷带固定。用药宜首选（）

A.土鳖虫

B.桃仁

C.红花

D.丹参

E.三棱

If you        talk about it with me,please wait till I finish my work at hand.

A．can

B．may

C．must

D．should