龍卷風

湖南長沙市長沙縣瑋思學校 王 瑩 編譯

What are tornadoes?

什么是龍卷風？

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

龍卷風也叫旋風，是垂直的漏斗狀高速旋轉的氣流。

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

龍卷風形成于溫暖、潮濕的空氣與寒冷、干燥的空氣對流時，是云層中雷暴的產物，同時常常伴有冰雹天氣。

Where and when?

什么時候，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.

這樣危險的風暴在全世界范圍內都會出現，但美國是龍卷風的高發地，每年約出現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.

龍卷風在一年中的任何時候都有可能形成，但最常出現的時間段是早春到夏季之間。盡管在一天之中，白天和夜里都有可能出現龍卷風，但大多數的龍卷風形成于傍晚時分。

Duration and Speed

持續時間和時速

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.

當龍卷風擊中地面時，它可能會持續幾秒鐘，也可能會長達3 個小時。龍卷風平均寬度約200 米，移動速度約48 千米/小時。大多數龍卷風的移動距離不會超過10 千米。

Dangerous!

危險！

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.

強風會摧毀房屋和商鋪。風還可能會摧毀橋梁和火車，讓汽車和卡車飛起來，把樹拉向天空，把河里的水都帶走。

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.

強風有時會將人推倒在地或拋向天空，從而導致人受傷或死亡。但大多數人在龍卷風中受傷的原因都是被破碎房屋的碎片——破碎的屋頂、碎玻璃、門和金屬碎片弄傷。

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?

(參考答案見本期第64 頁)

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