五脏分阴阳，肺的阴阳属性是（）
A.阳中之阳
B.阳中之阴
C.阴中之阳
D.阴中之阴
E.阴中之至阴
参考答案：B
They _______ put off the football game because of the rain yesterday. [ ]
A. had to
B. must
C. could
D. might
气阀阀面与阀座为外接触式配合，即阀面锥角小于座面锥角，通常小（）。
A．0.5°～1°
B．1°～1.5°
C．1.5°～2°
D．2°～2.5°
