部队过河在一个寒冷的冬天,一队士兵被一条河流拦住了去路。经勘测,河面虽已结冰,但只有五六厘米厚,上面还覆盖着一层厚厚的积雪。冰层的厚度不足以承载全副武装的士兵们经过。部队现在急需过河,但只有冰层的厚度达到七八厘米时行进才安全。大家正在着急的时候,一个士兵灵机一动,出了一个主意,使冰面的厚度在很短的时间内就达到了七八厘米。他是怎么做到的? Troops crossed the river On a cold winter, a group of soldiers was stopped by a river. After investigation, although the river has frozen, but only five or six centimeters thick, covered with a layer of thick snow. The ice is not thick enough to carry heavily armed soldiers. The troops are now in urgent need of crossing the river, but it is safe to travel only when the ice thickness reaches 78 centimeters. When everyone was in a hurry, a soldier had an idea and made an idea so that the ice thickness reached 78 centimeters in a very short period of time. How did he do that?