Snow crystals grow in one of two designs—plate-like and columnar.Plate-like crystals are flat.They form when the air temperature is about fifteen degrees below zero Celsius.Columnar snow crystals look like sticks of ice.They form when the temperature is about five degrees below zero.

　　The shape of a snow crystal may change from one form to another as the crystal passes through levels of air with different temperatures.When melting snow crystals or raindrops fall through very cold air，they freeze to form small particles of ice，called sleet.

　　Groups of frozen water droplets are called snow pellets.Under some conditions，these particles may grow larger and form solid pieces of ice，or hail.

　　When snow crystals stick together，they produce snowflakes.Snowflakes come in different sizes.As many as one hundred crystals may join together to form a snowflake larger than two and one-half centimeters.Under some conditions，snowflakes can form that are five centimeters long.Usually，this requires near freezing temperatures，light winds and changing conditions in Earth’s atmosphere.

　　Snow contains much less water than rain.About fifteen centimeters of wet snow has as much water as two and one-half centimeters of rain.About seventy-six centimeters of dry snow equals the water in two and one-half centimeters of rain.

　　Snowfall helps to protect plants and some wild animals from cold，winter weather.Fresh snow is made largely of air trapped among the snow crystals.Because the air has trouble moving，the movement of heat is greatly reduced.

【【译林湖南版】2011高考英语一轮复习提能训练：Module 2 Unit 3《Amazing people》（含解析）】相关文章：

★ 2017届江苏省淮安市新马中学高考牛津译林版英语一轮复习活动单：模块6 Unit 2《What is happiness to you》

★ （安徽专用）2014届高考英语一轮复习方案 作业手册（9）模块3 《Unit 9 Wheels》（含解析） 北师大版必修1

★ 2017高考四川省广安市英语阅读理解一轮系列训练：30（含解析）

★ 【三维设计】2017届高考英语（江苏专用）二轮复习课件：必修3 Unit 2《Language》

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (23)

★ 【浙江专用】2014届高考英语一轮复习课时作业(二十二)必修5Unit 2《The United Kingdom》

★ 【浙江专用】2014届高考英语一轮复习课时作业(三十)选修6Unit 5《The power of nature》

★ 四川省广安市2014高考英语一轮基础训练题（4）及答案

★ 安徽省淮南市2014高考英语一轮单项选择及文章训练（18）及答案

★ 安徽省淮南市2014高考英语一轮单项选择及文章训练（8）及答案