3星级宾馆的住宿价格在几个北方城市降得最多。Prices at three-star hotels fell furthest in several northern cities.北方的军队现在随时都可能大批越过新边界。Any day now, the Northern forces may pour across the new border.热带色彩在我们北方暗淡的光线下可能显得有点刺目。Tropical colours may ...
The impellers are kept in their proper relationship to each other by spur gear.液轮之间借助于正齿轮保持彼此正常的关系.Mainly by the impellers, pump body and pump cover composition.主要由叶轮 、 泵体和泵盖组成.Welding is one of the important technologie...