灭火战术原则中的先控制，是指把主要力量部署在火势发展蔓延的主要方向，对火势实施积极有效的控制。
参考答案：对
如果自然数有四个不同的质因数，那么这样的自然数中最小的是______．
The basic functions of a bill of lading is (are)（ ）.
A．a receipt for the goods which evidences the taking-over or loading by the carrier
B．an evidence of contract of carriage between the carrier and the shipper.
C．a document of title to goods.
D．All of the above.
