C.Don't enter the workforce if yoare not prepared with a bigger purpose.

D.Teachers are able to find jobs that are less demanding yet more rewarding.

[答案]B

25.Which of the following******in meaning to.

the underlined phrase"take a toll on"in the 1a*****.

A.Be in charge of

B.Be dependent on

C.Have an effect on

D.Take advantage of

[答案]C

阅读理解，回答26-30题

Passage 2

As a species,*****incredibly smart.We tell stories,create magnificent art and astounding technology,build cities,and explore space.We haven't been around nearly as long as many other species,but in many respects we've accomplished more than any*.We eat them and they don't eat us.We even run scientific***on them--and are thinking about re-creating

****those that have gone extinct.But our intelligence comes with a curious caveat:our babies are among the dumbest-or,rather,the most helpless--that exist.A baby******an stand within an hour of birth,and can even*****flee predators on its frst day of life.A baby monkey can grasp its mother and hang on for protection and nourishment.****infant

can't even hold up its own head.

The evolution of***intelligence isn't something that Celeste Kidd had ever pondered.A developmental cognitive scientist who currently works at the University of Rochester,her work had focussed mostly on learning and decision-making in children.Over years of***oung children,she became impressed with the average child's level of sophistication.But when she looked at the****sh encountered,she saw a baffling****of

helplessness:How****they be so incompetent one second and so so soon*****One day,she posed the question to her colleague Steven Piantadosi.

"Both of us wondered what could possibly justify the degree of helplessness human infants**she told me****."Even other primate babies,like baby chimps,which are close in evolutionary terms,can cling onto their moms."She began to see a contradiction:***are born quite helpless,far more so than any other primate,but,fairly early on,we start becoming quite smart,again far more so than any other primate.What if this weren't***so much as a causal pathway?

That's the argument that Kidd and***make in their new paper,published in a June issue of PNAS.Humans become so intelligent because***infants

are so incredibly helpless,they argue;the one necessitates the other.

The theory is startling,but it isn't entirely new.***have been pondering the peculiarities of our birth and its evolutionary significance for***some***.Humans***to the subset of mammals,****viviparous mammals,that give live birth to their young.This***that infants must grow to a mature enough state inside the body to be born,but they can't be so big that they are unable to come out.This leads to a trade-of:the more**

****an animal is,the larger its head generally is,but the birth canal imposes an upper limit o1n just how large that head can***it gets stuck.The brain,therefore,must keep maturing,and th*****continue growing,long after birth.***intelligent an animal will eventually be,the mor*****immature its brain is at birth.

Researchers have long known*****trade-off,*****the connection between brain size and neural density and intelligence.For instance,Robin****found that the ratio of neocortical volume to brain size can predict the social-group size in a****of species,****bats,cetaceans,and primates,

while Simon Reader has demonstrated links in tool use and innovation to brain size in primates.Kidd and*****new idea is that increased helplessness******mandates increased****in parents--and that a runaway

selection dynamic can account for both.Natural selection favors humans with******because those humans tend to be smarter.This may create evolutionary incentives for babies****born at an even earlier developmental stage,****require more intelligence to***.*This creates the dynamic:over time,helpless babies make parents more****.which makes babies more helpless,which makes the*****intelligent,and so on.

26.According to paragraph 1,***of the following is true?

A.Some species are smarter than human beings.

B.Extinct species have been re-created by scientists.

C.Babies of other species are smarter than human infants.

D.Fewer species are earlier inhabitants than human beings.

[答案]C

27.What surprised****Kidd regarding children's***maturation?

A.Infants'helplessness when they are born.

B.Children'S high intelligence when they grow up.

C.Children'S leap from helplessness to sophistication.

D.Children'S incompetence in learning and decision-making.

[答案]C

28.What can we***form Paragraph 3***brain development?

A.Babies'helplessness at birth is an indication of human intelligence

B.Other mammal brains are more mature than human brain at birth.