Wind is moving air. Air moves because of pressure differences. Air at the surface will want to move from an area of high pressure to one of lower pressure. The higher the pressure is, the heavier the mass of air above our heads, with air gently sinking. In low pressures, the air is rising away from the surface. Air needs to move to equalise this difference, hence we have winds. 风是流动的空气。
空气的流动是由于压力的差异。
地表空气会想要从一个高压区域移动到一个低压区域。
气压越高，我们头上的空气就越重，空气会慢慢下沉。
低压时，空气则从表面上升。
空气需要移动来平衡这种差异，因此就有了风。
风力的等级不用 level 表达我们说的“级”这个评级系统，英语中其实是这个词Beaufort scale/ bəufət/蒲福风力BeaufortThe Beaufort wind scale is a standard scale, running from force 0 for calm to force 12 hurricane and above for the description of wind speed. Each value represents a specific range and classification of wind speeds with accompanying descriptions of the effects on surface features. It was originally developed as a system for estimating wind strengths without the use of instruments.蒲福风级是一个风力级别标准，从0级平静到12级飓风及以上的描述风速的体系。
每个数值代表了风速的一个特定范围和分类，并附有对地表特征的影响的描述。
它最初是为不使用仪器来估计风力强度而研究出来的系统。
“今天刮5级风”英文正解是The wind reached Grade 5 on the Beaufort scale.今天的蒲福风力强度达到5级。
但，蒲福风力(Beaufort scale)是超专业的表达不学气象专业的歪果仁估计都不会说那"今天要刮5级大风"一般会怎么说呢?天气预报里一般不说风力级别而直接说风速：The winds will reach up to 24 mph today.今天的风速会达到每小时24英里。
mph = miles per hour(每小时英里数)kph = kilometers per hour(每小时公里数)风力级别和风速对应关系：在日常生活也可以这么表达：There will be a fresh breeze today.今天会刮强风。
不同的风速也对应了对风的不同的说法所以我们就可以直接用相应的词汇来表示同学们可以熟悉一下上面那个表格下回再和外国人聊"风"的时候就能更清楚啦~今天的内容都学会了么？欢迎评论交流心得~
