资产组合的方差由各资产的权重和方差决定，与各资产之间的协方差无关。()

未分类题By mentioning the encouragement of peoples saving, the author intends to______.A．emphasize the importance for people to be farsightedB．demonstrate the behavioral economics' influence on policy makingC．explain how behavioral economists earned the Nobel PrizeD．manifest that evolution has taking place in microeconomics

未分类题The underlined word in Paragraph 1 means______.A．lostB．prosperousC．fadingD．professional

未分类题According to the passage, a standard economic experience is that______.A．deficit finance is of value in economic crisisB．the stock market is in an irrational exuberanceC．markets may fail under some circumstancesD．humans are rational calculators

未分类题What do we learn from the text?A．Information technology is important for the transportation industry.B．The transportation industry has completed the task of using information technology to improve critical systems.C．Many people fail to realize the importance of the transportation industry.D．Many people fail to realize the importance of information technology.

未分类题The example of Britain indicates that______.A．a large proportion of waste is generated by developed countriesB．there are many other kinds of rubbish besides municipal wasteC．mining extraction generates large quantity of wasteD．agricultural waste makes up a large proportion of the total

未分类题The second paragraph mainly demonstrates______.A．space garbage's hazard towards peopleB．that people produce waste of all kinds with large amountC．whether people should take recycling into accountD．Ken Noguchi's five clean-up expeditions

未分类题When does Miralda-Escude estimate the first star appeared?A．75 million years ago.B．14 billion years ago.C．14 billion years after the big bang.D．75 million years after the big bang.

未分类题By mentioning an organization in San Diego, the author intends to______.A．encourage institutions to do interdisciplinary researchesB．state many institutions strive to study set environment's influence on humansC．prove that researches in neuroscience have been in popularityD．advocate that architecture schools should involve introductory neuroscience

未分类题We can learn from Paragraph 1 that______.A．the average adult sleeps one and a half hours less than last centuryB．24-hour entertainment offers those who can't sleep a way to kill timeC．lack of sleep may harm one's health and even threaten his her lifeD．people always don't have the incentive to get more sleep

未分类题How does the author feel about the current lack of technological literacy?

未分类题The underlined word in Paragraph 1 means______.A．obligationB．sleepC．hibernationD．vacation

未分类题According to the text, the purpose of RoboCup is to______.A．create a world ruled by robotsB．eliminate the need for human athletesC．test out artificial intelligence technologyD．for scientists to get together and have a good time

未分类题Mole rats are similar to humans in that they______.A．are virtually hairlessB．live in underground coloniesC．have opposable thumbsD．are able to kill parasites

未分类题Which of the following is the best title for the text?A．Everyone desires a good night's sleepB．A study on less sleep's jeopardyC．More sleep doesn't mean better lifeD．Less sleep, more heart disease

未分类题According to the author, technology______.A．is the key to eliminating the gap between the rich and the poorB．has led to many of society's fundamental changesC．is literateD．has caused war to be focused more heavily on nuclear confrontation