“阴者，藏精而起亟也；阳者，卫外而为固也”说明阴阳的（）。
A.制约
B.交感
C.消长
D.互根
E.互用
参考答案：E
---I have tried very hard to find a solution to the problem, but in vain.
---Why not consult with Frank? You see, .
A．great minds think alike
B．two heads are better than one
C．a bird in the hand is worth two in the bush.
D．it’s better to think twice before doing something
They didn't go to bed ______ they finished their homework. [ ]
A. until
B. because
C. when
D. if
