必修三模塊四 Sandstorms in Asia學案

(show the words on the screen, and explain the meaning to the students. divide the whole class into several groups to discuss questions in activity 2. then call back the answers)
s1: most of the sandstorms begin in desert areas. because there are no trees and grasses in the    desert areas. the wind is very strong.
s2: climate changing can create deserts, but nowadays, the deserts are being enlarged because of humanity.
s3: deserts are also created because people cut down trees and dig up grass.
t: why people cut down trees?
s3: they want to get wood or to plant crops.
s4: few years ago, japan was affected by the sandstorms coming from northwest china. and america is also affected by sandstorms. some are caused by humanity; some are from asia blown across the pacific ocean. sandstorm has been a global issue.
t: very good, thank you. can we prevent it?
s5: yes. at present, our china has carried out many plans to prevent sandstorm. for example, china has formed a professor committee to study how to prevent sandstorms. we have planted many trees every year. cutting down the trees is unlawful. the degree of sandstorm is on decline. so we can prevent it. we believe ourselves.
t: quite right. i believe too. where does the sandstorm often happen?
s6: the inland region has more sandstorms than the one near the sea. because the inland is drier than the one near the sea.
t: can you give us the reason?
s6: dry weather is one of the main reasons for sandstorms.
t: quite right. you’ve done very well. from this activity, you’ve got much information on sandstorms. sandstorm is very bad. it pollutes the air, affects our daily life. if you are in a sandstorm what should you do? now work in pairs to discuss the questions in activity 3.
(5 minutes later, call back the answers)
s1: if i am in a sandstorm i will wear a mask to protect my mouth and throat, wear a pair of glasses to protect my eyes.
s2: besides mask and glasses i will wear a hat. because there is much sand in the air, it will make my hair dirty.
t: you are right. in a sandstorm, you should wear a mask and a hat, a pair of glasses is also necessary. which one is more dangerous, earthquake and sandstorm?
s3: i think earthquake. because in sandstorm we can stay at home to protect us, but in earthquake everywhere is dangerous.
t: i agree with you. where in china do sandstorms usually happen? what is the first sign?
s4: in the west and northwest china.
s5: but it also happens in beijing often.
s6: before the sandstorm, there is usually a heavy wind and dry weather.