They form when a layer of relatively stable and moist air - stream is forced to rise by hills , causing up and down wave motions in the air . the rising air in the wave causes the moisture to cool down and condense into water droplets , which then become visible to the eye 它的成因是当一层较为稳定及潮湿的空气遇到山脉而被迫抬升，引起上下起伏的波浪，而在波浪中上升的气流令潮湿的空气变冷，凝结成水点，使我们可以用肉眼看见。
Hotel guests who have a fever , cough , respiratory symptoms or signs of infection should not use common showers , saunas , jacuzzis or spas such as those provided in hotel health clubs or gyms as a moist atmosphere will aggravate the spread of respiratory viruses 如住客有发热咳嗽呼吸道感染症状或其他传染病病徵，则不应使用公共淋浴设施桑拿浴室按摩浴池或矿泉浴场例如酒店会所或健身中心附设者，以免潮湿的空气加剧呼吸道疾病的传播。
Walks in the winter rain deep and clear street corner , the rainmoistens my body , dissolves soft water ; i did not know that rain isdisappointed but the ache because of my innermost feelings only thento break to pieces , perhaps is some kind of mood causes however , icannot wield this moist air 走在冬雨潇潇的街头，雨打湿我的身体，溶成一片柔软的水；我不知道那雨是不是因为我内心失望而疼痛才碎，也许是某种情绪的使然，我挥不去这潮湿的空气。
Hotel guests who have a fever , cough , respiratory symptoms or signs of infection should not use common showers , saunas , jacuzzis or spas ( such as those provided in hotel health clubs or gyms ) as a moist atmosphere will aggravate the spread of respiratory viruses 如住客有发热、咳嗽、呼吸道感染症状或其他传染病病徵，则不应使用公共淋浴设施、桑拿浴室、按摩浴池或矿泉浴场(例如酒店会所或健身中心附设者) ，以免潮湿的空气加剧呼吸道疾病的传播。
