三补三泻
参考答案：指六味地黄丸组方用药特点。即本方组成中熟地黄、山茱萸、山药，谓“三补”；茯苓、泽泻、丹皮谓“三泻”。
You should understand the traffic rule by now. You've had it _____ often enough. [ ]
A. explaining
B. to explain
C. explain
D. explained
法律规定代位权的成立应具备法定要件，以下不属于此要件的是( )。
A．债务人无力行使其债权
B．债务人怠于行使权利的行为对债权人造成危害
C．债权人有保全债权的必要
D．债务人没有能力行使其债权
