导致滑胎的机理有二：其______；其二______。
参考答案：母体冲任损伤 胎元不健
The doctor told Mary to eat _____ vegetables and _____ meat because she was getting fatter and fatter. [ ]
A. much; little
B. more; less
C. many; few
D. more; fewer
怎样在公共场所构建良好的人际互助关系？
