Weknowthatmanyanimalsdonotstayinoneplace.Birdsfishandotheranimalsmovefromoneplacetoanotheratacertaintime.Theymovefordifferentreasons:mostofthemmovetofindfoodmoreeasilybutothersmovetogetawayfromplacesthataretoocrowded.

Whencoldweathercomesmanybirdsmovetowarmerplacestofindfood.Somefishesgivebirthinwarmwaterandmovetocoldwatertofeed.Themostfamousmigration(迁移)isprobablythemigrationofthefishwhichiscalledthe“salmon”.Thisfishisborninfreshwaterbutittravelsmanymilestosaltwater.Thereitspendsmostofitslife.Whenitisolditreturnstoitsbirthplaceinfreshwater.Thenitgivesbirthanddiesthere.InnorthernEuropethereisakindofmicethatleavetheirmountainhomeswhentheybecometoocrowded.Theymovedowntothelowland.Sometimestheymoveallthewaytotheseasideandmanyofthemarekilledbyfallingintothesea.

Recentlyscientistshavestudiedthemigrationofakindoflobsters(龙虾).Everyyearwhentheseasonofbadweatherarriveslobstersgetintoalonglineandstarttowalkacrosstheflooroftheocean.Nobodyknowswhytheydothisandnobodyknowswheretheygo.

Sosometimesweknowwhyhumansandanimalsmovefromoneplacetoanotherbutatothertimeswedon’t.Maybelivingthingsjustliketotravel.

1.Mostanimalsmovefromoneplacetoanotheratacertaintimeto____.

Agivebirth Benjoyawarmclimate

Cfindfoodmoreeasily Dfindbeautifulplaces

2.Thefishcalled“salmon”spendsmostofitstimein____.

Asaltwater Brivers Cfreshwater Ditsbirthplace

3.AkindofmiceinnorthernEuropemovewhen____.

Atheygivebirth Btheweatherbecomesbad

Ctherearetoomanyoftheminoneplace Dtheyhaven’tenoughfood

4.Whatisthemainideaofthepassage?

AAnimalsmoveinordertofindfoodmoreeasily

BThemigrationofthefishcalled“salmon”isthemostfamousmigration

CLivingthingsmovefromoneplacetoanotherbecausetheyliketotravel

DSometimesweknowwhyandhowlivingthingsmovefromoneplacetoanotherbutsometimeswedon’t.