痛经的主要病机是（）
A.寒凝血瘀
B.气血运行不畅
C.湿热阻滞
D.阳虚内寒
E.血海空虚
参考答案：B
---What do you enjoy most in life?
---____________ time _________ books. It’s really good fun.
A．Spend; read
B．Spending; to read
C．To spend; to read
D．Spending; reading
锯割硬材料或切面较小的工件，应该用（）锯条。
A、硬齿
B、软齿
C、粗齿
D、细齿
