小儿开始能独坐的月龄是()
A.3个月
B.4个月
C.5~7个月
D.8~10个月
E.10~12个月
参考答案:C
解析:5个月靠坐时腰能伸直,7个月能独坐片刻
72. At the beginning, I had some difficulty with my English, and my teacher pulled me ______.
A.down
B.over
C.up
D.Through
土壤在植物生长中的作用是什么?