堆垛时，叉车门架必须尽量后倾，以保证载荷稳定。
参考答案：错
All of the following could be objectives of a passive investor in commodities, except:（）
A. Risk diversification.
B. Inflation protection.
C. Anticipating good performance during periods of economic growth.
上颌第一磨牙较高的髓角一般接近于（）
A．牙冠1/3
B．牙冠中1/3
C．牙冠颈1/3
D．牙冠1/3与中1/3交界处
E．以上都不是
1/3