Why does the author mention "the Louisiana Purchase"？

A.To give an example of the various reasons for road accidents. B.To show how important it is for drivers to be emotionally healthy. C.To show some of the inaccurate estimations by researchers. D.To illustrate the hidden tensions in the course of driving.

A.To describe some unusual kinds of pets． B.To measure distances trailed by various animals． C.To compare their home-finding abilities with those of homing pigeons． D.To interest the reader in learning about other animals．

A.Because they are easy to steal. B.Because they are difficult for people to obtain. C.Because they are not easy to carry around. D.Because they themselves are expensive， too.

A．To indicate that watching news is common in the evening. B．To explain America's cultural invasion of France. C．To give an example of the acceptance of American culture. D．To show that France has submitted to America.

A．Because this is the need of both sides' interests. B．Because the U. S. has long had a good relationship with Europe. C．Because the U. S. always takes its role in global leadership. D．Because this could help build a strong partnership.

A.Because they make science exciting. B.Because they promote economic growth. C.Because they increase Americas national power. D.Because they show what technology can bring.

A.They ale approximately the same size． B.They shale many similar species． C.Most of their inhabitants require water． D.Both have many different forms of life．

A．Because they loved animals so much. B．Because animals were the frequent subject of their paintings. C．Because they needed them to form. a religion. D．Because they wanted to live in safety, preventing themselves from being hurt by animals. 此题为多项选择题。

A．Because he treats the car industry as the key point for his writing. B．Because the car industry is more important than table market. C．Because he uses the car analogy for a more effective argumentation. D．Because the model of the car is far more popular in the market.

A．To warn about possible risks involved in phytoremediation B．To help illustrate the potential of phytoremediation C．To show that hyperaccumulating plants grow in many regions of the world D．To explain how zinc contamination can be reduced

A.Herealizesthereisagreatdividebetweenhislifeandthatofblue-collarworkers. B.Helooksdownuponthemechanicalworkattheassemblyline. C.Hehasnotdonemuchtohelphisco-workersatthefactory. D.Hehasstayedatschooljustforthepurposeofescapingfromtherealworld.

A．To illustrate methane's molecular structure. B．To show the link between global warming and smog. C．To suggest that fossil fuels should not be burned. D．To elaborate on a benefit of natural gas's cleanliness.

A．To describe how the differences between Pleistocene and Cambrian quartz reveal information about dating rocks B．To point out that the chemical composition of quartz makes it more difficult to date than other rocks C．To provide an example of how regional differences in rock sequences can make a particular rock difficult to date D．To explain that rocks are difficult to use for dating because their chemical compositions always remain the same over time

A．To give examples of modern groups in which women participate in net hunting B．To demonstrate how net hunting should be carried out in modern societies C．To describe net hunting techniques that protect the women in the group D．To contrast their net hunting techniques with those of the people in the Congo

A．To suggest that most of the ancient Greeks were wealthy B．To show that the period was a high point in Greek civilization C．To argue that Greece was the only society with a political system D．To explain why the population of Greece was growing rapidly

A．Because they are the origin of the myxoma virus B．Because they carry the myxoma virus to other animals C．Because they die when they are infected by myxoma D．Because they have an immunity to the myxoma virus

Why does the author mention "there is wide-spread uneasiness and confusion"(Para. 1)？______ A．The abundant food supply is not expected to last B．Britain is importing less food C．Despite the abundance, food prices keep rising D．Britain will cut back on its production of food

A．Because their typed dialogue online can cause misinterpretation． B．Because the computer keeps crashing． C．Because her boyfriend lacks emotional care for her．