训练17阅读理解完形填空语法填空短文改错(建议用时45分钟).阅读理解Even if trees cannot walk，they are still on the move.In parts of the Arctic，entire forests are moving northward.Across the Arctic，temperatures are rising faster than anywhere else in the world.As that happens，the tree line that marks where forests stop and the treeless tundra (冻原) starts has been shifting northward.Trees growing along the tree line must protect themselves from the cold wind.To do this，plants tend to grow horizontal (水平的)branches low to the ground.The energy it takes for trees to grow this way means they dont have enough energy to make seeds.But as Earths climate has been warming，trees no longer have to just grow horizontally.Many can instead grow up toward the sky.This takes less energy.And with all that leftover energy，these trees have started producing more seeds.This happens especially in places where white spruce (白云杉) grows.White spruce，which is a North American tree，is quite able to produce a lot of seeds，which can move long distances in the wind.When windblown seeds end up on the tundra beyond the tree line，they eventually can sprout (发芽) new trees.This explains how a forest can move.Of course，the process would work only if the tundra were warm enough.But in recent years，the whole planet has been warming.New trees will provide shelters for some snow.Keeping the suns rays from making the white surface disappear.Instead，the trees absorb the suns heat.This warms the surrounding air.The extra warmth encourages even more trees to produce seeds.That further boosts a forests ability to expand.In addition，more trees will trap more snow，preventing much of it from being blown away.Snow can trap heat in the soil below，which encourages trees to grow.The recent rise of temperatures has helped more trees grow past the tree line.People worry about impacts on the animals that depend on frozen conditions for food and shelter.1What is the main cause of the trees in the Arctic moving northward?AThe shrinking of northern tundra.BThe rising temperature.CThe fierce and cold wind.DThe abundant resources in the north.2What does the underlined word “ this” in Paragraph 2 mean?ATo produce more seeds.BTo move northward.CTo respond to the climate change.DTo protect themselves from the cold wind.3What can be inferred from the last paragraph?ANew trees can trap the snow，which may make the soil colder.BThe trapped snow prevents new trees from producing more seeds.CNew trees can make the surrounding air warmer.DNew trees can bring more food and shelter to local animals.4The passage is most probably taken from _.Aa science report Ba health reportCa fashion magazine Da childrens magazine【语篇解读】本文是一篇科研报告，主要研究了气温升高对北极圈植物的影响。1解析：选B。根据第二段的第二句“Across the Arctic，temperatures are rising faster than anywhere else in the world”以及本段的整体内容可知，不断上升的气温是北极圈树木北移的主要原因，即B项正确。2解析：选D。根据画线词前的“Trees growing along the tree line must protect themselves from the cold wind”可知，画线词this指代的是本句中的“protect themselves from the cold wind”，即D项正确。3解析：选C。根据最后一段中的“New trees will provide shelters for some snow.Keeping the suns rays from making the white surface disappear.Instead，the trees absorb the suns heat.This warms the surrounding air”可推知，新树会让周围的空气更加温暖，即C项正确。4解析：选A。根据文章的整体内容可推知，本文主要研究的是气候变暖对北极圈植物的影响，故该文应选自科研报告，即A项正确。.完形填空Getting StartedChriss parents were proud of him when he graduated from college.But its been six months and he hasnt got a job yet.In fact，he hasnt _1_ seriously.He has no idea what he wants to do and hes thinking of grad school.Hes living at home with his parents and things are getting _2_，especially with his father，who _3_ Chris of being lazy and afraid to enter the real world.Chris thinks his dad is being totally _4_.After all，hes only young once and he needs some “ _5_ ”During a recent argument，Chris said，“Im not you，Dad.I have my own way of doing things.I want a job I _6_.”His dad replied，“Thats a nice idea，but in the end they call it work_7_ its about making a productive livingnot having _8_.”There are many youngsters like Chris who are having trouble getting started _9_ a serious job and becoming independent.Some，like Peter Pan，just dont want to _10_.Some are afraid of making a wrong decision or of being rejected.Others are _11_ of what psychologists call “magical thinking”They believe that when the _12_ is right，everything will fall into place.So they wait for _13_ to come knocking or until they feel inspired or excited about their next step._14_，it doesnt work that way.Whats important is to _15_.Things happen and opportunities appear most often when were _16_，not standing still.Energy is very important.Basic physics says its easier to _17_ the course of a moving object than to start _18_ initially.In the end，its not really about finding yourself.Its about _19_ you