Adesertisalargelandofsand.Thereisverylittlerainandnotmanyplants.Thesizeandtheplaceoftheworld’sdesertsarealwayschanging.Inrecentahundredyearsdesertshavebecomemoreandmore.That’smainlybecauseofmen.InthenineteenthcenturysomepeoplebroughtakindoflittleanimalcalledrabbittoAustraliafromEngland.Todaytherearemillionsofthem.Theyeateveryplanttheysee.SothegreatdesertinthecenterofAustraliaisbecomingbigger.

ThereareplacesinNorthAfricawheregreatcitiesoncestood.Thereweregardensandtreesandgrass.Butnowtheseplacesaredeserts.Scientistsstudiedthelandtofindoutwhathappened.Manyofthemthoughtthelanddiedwhenthetreeshadbeencutdown.

Treeshelpotherplantsgrow.Andtheykeeptheearthfromblowingaway.Inforestsleavesonthegroundkeeprainwaterfromrunningoff.

Men can make desertsbuttheycan alsostopthemfrom getting bigger. For examplein Chinathe GreatGreenWallhasbeenbuilt andithasalreadysaved a lot ofland. But more “Great GreenWall”arestillneededallovertheworld.Canwestopdesertsfromgettingbiggerandsavetheland?Yeswecan.Andwemust.

1.选择最佳答案。

( )1)Whatisadesertinthetext?

A.Largelandofearth. B.Alargelandofgrass.

C.Alargelandofsand. D.Alargegoodland.

( )2)Whichdesertisbecomingbigger inthetext?

A.Thegreatdesertinthe northwestofChina.

B.Thegreatdesertinthe middleofAmerica.

C.ThegreatdesertinthemiddleofAustralia.

D.ThegreatdesertinSouthAfrica.

( )3)Whostudiedtheplaceswhicharedeserts now?

A.Scientists. B.Teachers. C.Workers. D.Students.

( )4)Fromthetextweknow .

A.treeshelpotherplantsgrowand keep the earthfromblowingaway

B.desertsaregoodplacesfortreestogrow

C.rabbitscanmakedesertsbecomegoodland

D.thereisplentyofrainandmanyplantsinthedeserts

( )5)Whatcanpeopledowithdeserts?

A.Theycandonothing.

B.TheycanbuildGreatGreenWallstochangethedeserts.

C.Theycanplantmanyflowersthere.

D.Theycangooncut