阶梯倍投方案12244原理简介：The hillside Song Yuhe chose was very steep, with a slope of fifty or sixty degrees, and the soil was so soft that the sand could reach the ankles when one stepped on it, so it was very difficult for the Japs to climb.
The hillside Song Yuhe chose was very steep, with a slope of fifty or sixty degrees, and the soil was so soft that the sand could reach the ankles when one stepped on it, so it was very difficult for the Japs to climb.
