Weknowthatmanyanimalsdonotstayinoneplace.Birds,fishandotheranimalsmovefromoneplacetoanotheratacertaintime.Theymovefordifferentreasons:mostofthemmovetofindfoodmoreeasily,butothersmovetogetawayfromplacesthataretoocrowded.

Whencoldweathercomes,manybirdsmovetowarmerplacestofindfood.Somefishesgivebirthinwarmwaterandmovetocoldwatertofeed.Themostfamousmigration(迁移)isprobablythemigrationoffish,whichiscalled“salmon”.Thisfishisborninfreshwaterbutittravelsmanymilestosaltwater.Thereitspendsitslife.Whenitisold,itreturnstoitsbirthplaceinfreshwater.Thenitgivesbirthanddies.InnorthernEurope,thereisakindofmouse.Theyleavetheirmountainhomeswhentheybecometoocrowded.Theymovedowntothelowland.Sometimestheymoveallthewaytotheseaside,andmanyofthemarekilledwhentheyfallintothesea.

Recently(近来),scientistshavestudiedthemigrationofakindoflobster(龙虾).Everyyear,

whentheseasonofthebadweatherarrives,thelobstersgetintoalonglineandstarttowalk

acrosstheflooroftheocean.Nobodyknowswhytheydothis,andnobodyknowswheretheygo.

So,sometimesweknowwhyhumansandanimalsmovefromoneplacetoanother,butatother

timeswedon’t.Maybelivingthingsjustliketotravel

1.Mostanimalsmovefromoneplacetoanotheratacertaintimeto_______.

A.givebirthB.enjoywarmerweather

C.findfoodmoreeasilyD.findbeautifulplaces

2.Thefishcalled“salmon”spendsalongtimein______.

A.saltwaterB.riversC.freshwaterD.itsbirthplace

3.ThemiceinnorthernEuropemovewhen_______.

A.theygivebirthB.theplacegetstoocrowded

C.theweatherisbadD.theyhaven’tenoughfood

4.Thelobstersmove________.

A.tothefreshwaterB.atacertaintimeC.totheunderseaD.tofindmorefood

5.Whatisthemainideaofthepassage?

A.Animalsmovetofindfoodmoreeasily.

B.Themigrationofthefishcalled“salmon”isthemostfamousmigration.

C.Livingthingsmovefromoneplacetoanotherbecausetheyliketotravel.

D.Sometimesweknowwhyandhowlivingthingsmovefromo