3.Have you ever looked toward the sky on a fall day and witnessed a group of migrating birds?If so,you probably noted the V-shaped formation of the birds or the birds flying in a ball-like formation.Why do birds fly this way?Many theories have been developed to explain the formation patterns of different types of birds.
One theory is that birds fly in certain formations to take advantage of the laws of nature.The birds know that flying in a V-shaped pattern will save energy.Like the lead cyclist in a race who decreases wind force for the cyclists who follow,the lead bird cuts wind force for the birds that follow.This decrease in wind force means that the birds use up to 70percent less energy during their flight.When the lead bird becomes tired,a more rested bird takes over that position.
But saving energy is important for more than one reason.Sometimes food is short during migration flights.Keeping energy enables the birds to fly longer distances between meals.
When food is sighted,the birds guide one another in a different way.When a bird identifies a familiar feeding area,it might turn around in order to signal the group to change direction.Then,this bird becomes the new leader.It helps guarantee that other birds will know exactly where it is going.Then the whole group makes a change in direction,gently streaming from the sky down to the ground.This formation is like an arrow pointing to the location of food.
Scientists have also studied the birds that sometimes fly in a ball-like formation.Researchers believe that the birds come together if a predator (天敵) is spotted.The predator may then become impatient waiting for a single bird to fly away from the group.The birds will often dip and dive as a group,frustrating even the most persistent enemy.Scientists report that this is a very effective method of defense against an attack.
The birds care for their fellow fliers through teamwork.As transportation expert Henry Ford once said,"If everyone is moving forward together,then success takes care of itself."When it comes to teamwork,these feathered fliers are a soaring success!
43.According to the passage,we can learn that birdsC.
A.move faster than cyclists
B.a(chǎn)re smarter than other animals
C.play different roles in a formation
D.prefer to fly in a V-shaped formation
44.When food is sighted,A.
A.the group follows the discoverer
B.the lead bird decides what to do
C.the discoverer leaves the group
D.the whole group forms a stream
45.To protect themselves from attack,birds willD.
A.break into groups B.come close together
C.change directions D.fly up and down
46.Which is the best title for the passage?A
A.A Bird's-Eye View Of Teamwork
B.Success Takes Care Of Itself
C.The Strongest Will Survive
D.A Science Behind Flying.
分析 文章主要是從鳥兒整體的角度去分析它們各種習(xí)性,要凸顯出它們的團隊合作精神.
解答 CADA
43 C 文章沒有提到遷徙的鳥比騎自行車的人快.根據(jù)第一段you probably noted the V-shaped formation of the birds or the birds flying in a ball-like formation.可知B不正確.D文章沒有提到.通讀文章可知在隊形中各有各的職責(zé).故答案選C.
44 A 根據(jù)第四段中When a bird identifies a familiar feeding area,it might turn around in order to signal the group to change direction.Then,this bird becomes the new leader.可知哪只鳥發(fā)現(xiàn)了食物就會成為新的領(lǐng)頭者.故答案選A.
45 D 根據(jù)第五段可知當鳥類遇到其他動物的襲擊的時候會選擇像球形的形狀.The predator may then become impatient waiting for a single bird to fly away from the group.這樣它們的敵人就不容易襲擊它們.故答案選D.
46 A 根據(jù)最后一段可知作者講鳥類的團結(jié)合作,是為了讓我們從中得到啟示,故答案選A.
點評 考察學(xué)生的細節(jié)理解和推理判斷能力,做細節(jié)理解題時一定要找到文章中的原句,和題干進行比較,再做出正確的選擇.在做推理判斷題不要以個人的主觀想象代替文章的事實,要根據(jù)文章事實進行合乎邏輯的推理判斷.