龙卷风

湖南长沙市长沙县玮思学校 王 莹 编译

What are tornadoes?

什么是龙卷风？

Tornadoes,also called twisters,are vertical funnels of rapidly spinning air.

龙卷风也叫旋风，是垂直的漏斗状高速旋转的气流。

Tornadoes form when warm,humid air mix with cold,dry air.Tornadoes are born in thunderstorms and often come with hail.

龙卷风形成于温暖、潮湿的空气与寒冷、干燥的空气对流时，是云层中雷暴的产物，同时常常伴有冰雹天气。

Where and when?

什么时候，在哪里？

These dangerous storms occur around the world,but the United States is a place with the most,with about 1000 tornadoes every year.

这样危险的风暴在全世界范围内都会出现，但美国是龙卷风的高发地，每年约出现1000 次。

Tornadoes can occur at any time of year,but they are more common from early spring to summer.Although they can form at any time of the day or night,most tornadoes form in the late afternoon.

龙卷风在一年中的任何时候都有可能形成，但最常出现的时间段是早春到夏季之间。尽管在一天之中，白天和夜里都有可能出现龙卷风，但大多数的龙卷风形成于傍晚时分。

Duration and Speed

持续时间和时速

When a tornado hits the ground,it may live for as little as a few seconds or as long as three hours.The average twister is about 200 meters wide and moves about 48 km/h.Most don’t travel more than 10 km before stopping.

当龙卷风击中地面时，它可能会持续几秒钟，也可能会长达3 个小时。龙卷风平均宽度约200 米，移动速度约48 千米/小时。大多数龙卷风的移动距离不会超过10 千米。

Dangerous!

危险！

Very strong winds break homes and businesses.Winds can also destroy bridges and trains,send cars and trucks flying,pull trees into the sky,and take all the water out the rivers.

强风会摧毁房屋和商铺。风还可能会摧毁桥梁和火车，让汽车和卡车飞起来，把树拉向天空，把河里的水都带走。

Strong winds sometimes kill or hurt people by pushing them to the ground or throwing them into the sky.But most people get hurt by flying debris from broken houses—parts of the roof,broken glass,doors,pieces of metal.

强风有时会将人推倒在地或抛向天空，从而导致人受伤或死亡。但大多数人在龙卷风中受伤的原因都是被破碎房屋的碎片——破碎的屋顶、碎玻璃、门和金属碎片弄伤。

I.Yes or No?

1.Tornadoes are also called twisters.( )

2.There are about 10,000 tornadoes in the United States every year.( )

3.Most tornadoes can travel more than 10 km before stopping.( )

4.Tornadoes are more common from early spring to summer.( )

5.Most tornadoes form in the late afternoon.( )

II.Fill in the blanks.

1.Tornadoes are vertical funnels of _______.

2.Tornadoes form when _______ air mix with _______ air.

3.The average twister is about _______ wide and moves about_______.

III.Answer the question.

Why are tornadoes dangerous?

(参考答案见本期第64 页)

Keys toSpecialized Training in Mixed Operations (4A)

I.(1) 452 (2) 23 (3) 14 (4) 165 (5) 96 (6) 124 (7) 791 (8) 2160 (9) 555(10) 92

II.(1) 60 (2) 6……2 (3) 4……3 (4) 9;0 (5) 56 (6) 63 m (7) 11 (8) 550 km(9) 45;15 (10) A=390;B=710