Fire retardants are materials that can stop or slow the spread of fires.

防火剂这种物质可以阻止或者减缓火势的蔓延。

It's designed specifically to look at the effects of slope on the flame characteristics and on the spread of fires.

它被专门设计来观察斜坡对火焰特性和火灾蔓延的影响。

Another huge unknown in the spread of fires to the boreal regions is peat.

火势蔓延至北方地区的另一个巨大未知因素是泥炭。