HCMW炉卷轧机的特点（）
A、强压下
B、高钢度
C、辊径小
D、以上都是
参考答案：D
To our _____, China overcame all the difficulties caused by the disasters in 2008 and successfully hosted
the 29th Olympic Games. [ ]
A. wonder
B. doubt
C. credit
D. point
简述作物生产力估算的重要意义。
