What does the author mean by saying that the Grand Canyon is of relatively recent origin？

A . There’S been nothing but rain for quite some time． B . He’S bored with the changing weather． C . He thinks that it’11 rain for three more weeks． D . He’S bored about the topic on weather．

A . here is still a long way to go for economists to genuinely contribute to global health. B . Economists＇ role in global health is, to a large extent, negative C . Economists increased the inequality of resource allocations in global health D . Economics is only one science among many that policy makers have to take into account in providing health care programs

A．The Eastern employees will experience more pains. B．The Eastern employees will lose their jobs as the Westerns. C．The Eastern employees will get fewer incomes. D．The Eastern employees won't get any pay in one year.

A．The definition is not precise. B．The discussion lacks necessary information. C．The differences are probably significant. D．The comparison is quite appropriate.

A．Technologies for carbon reduction in all industries, including aviation, do not exist yet. B．Technologies are not available for carbon reduction with the current aircraft models. C．Technologies designed to cut pollution from electricity generation and from air travel are not the same. D．Technologies to cut carbon from power plants cannot be used to cut carbon from planes.

A．Friendly animals such as dogs should have been introduced. B．Men should remove the bad effect caused by cats. C．Man should have a better understanding of cats. D．Cats are not as valuable as other rare animals.

A.He wants to go with them． B.He will invite his friends． C.He is not interested in going．

A．Different families have different ways of life. B．Different definitions could be given to the word. C．Different nations have different families. D．Different times produce different families.

A.Exercising can"t help reduce the harm caused by sitting. B.The harm depends on the prolonged time sitting at a desk. C.Exercising is not necessary for people. D.Exercising has no advantages for people who often sit.

A.People don"t pay attention to their health. B.Few people are willing to support travel medicine. C.Most travellers firmly believe that they will be safe. D.Health comes last compared with others.

A．Wireless recharging is too wonderful to be true. B．Wireless recharging is consistent with the laws of nature. C．Wireless recharging will definitely come true finally. D．Wireless recharging will surely enter the mainstream in the end.

A. Continuing education is more important to a person success. B.A person happiness should be valued more than their education. C. Kids actual abilities are more important than their college background. D. What kids learn at college cannot keep up with job market requirements.

A．Going to several different schools is educationally beneficial. B．School vacations interrupt the continuity of the school year. C．Summer school makes the school year too long. D．All of life is an education.

A．The person gives the real meaning to the word, not the word itself B．The word has no meaning C．We need to understand what a person says D．We need to know the speaker so that we may understand him

A．Geron ends government interference in this area. B．Geron settles the disputes over stem cell research. C．Geron follows up the research on their own. D．Geron rallies for the research.