74．In the botanist's opinion, man needs to __________.
A．enable Mars to clean its atmosphere
B．build a greenhouse on Mars
C．send some people to settle on Mars
D．cultivate ecosystems from lower to higher life form
73．What does the author think of the idea ofterraforming Mars?
A．We could do it． B．We couldn't do it．
C．We should do it． D．We shouldn't do it．
72．What is the most essential to make Mars fit for living?
A．Turn ice into flowing water． B．Clean the dirty atmosphere．
C．Make the atmosphere more suitable． D．Go to the moon or an asteroid first．
71．Apart from altitude, how many factors raise the chance of developing heart disease?
A．three B．Four C．Five D．Six
E
Could we "terraform" Mars -that is, change its frozen, thin-aired surface into something more friendly and Earthlike? Should we? The first question has a clear answer: Yes, we probably could．Spacecraft, including the ones now exploring Mars, have found evidence that it was warm in its youth, with rivers flowing into vast seas．And right here on Earth, we've learned how to warm a planet: just add greenhouse gases to its atmosphere．Much of the CO2 that once warmed Mars is probably still there, in frozen dirt and polar ice caps, and so is the water．
Most of the work in terraforming, says NASA scientist Chris Mackay, would be done by life itself． "You don't build Mars," Mackay says．"You just warm it up and throw some seeds．" Powerful greenhouse gases could be produced from elements in dirt and air on Mars and blown into the atmosphere; by warming the planet, they would release the frozen CO2, which would quicken the warming and increase atmospheric pressure to the point where liquid water could flow．Meanwhile, says botanist James Graham of the University of Wisconsin, human settlers could seed the red rock with a succession (系列) of ecosystems ?first bacteria and lichens (地衣), which survive in Antarctica, later mosses (苔藓), and after one thousand years or so, redwoods．Getting breathable oxygen levels out of those forests, though, could take thousands of years．
However, Mars is in no immediate danger．Some space scientists recently recommended going to the moon or an asteroid (小行星) first, and pointed out the space agency lacks the funds to go anywhere．It didn't estimate the cost of gardening a dead planet．
70．How long does the research of the Greeks last?
A．At most 10 years． B．About 15 years．
C．More than 20 years． D．Not mentioned．
69．According to the passage, a person _________ may have less possibility of having heart attack.
A．with more money B．with a better living habit
C．from higher altitude D．in a happier mood
68．The first sentence in the passage is used to __________．
A．tell readers what the passage focuses on
B．give a very good guessing
C．warn people of the risk of heart disease
D．name a new unknown illness
67．What is the author's attitude toward Charoulette?
A．Positive． B．Supportive． C．Objective． D．Negative．
D
If you want to live longer and lower the risk of heart disease, a move to the mountains may help． Research by scientists in Greece shows that living in the mountains is good for the heart and longevity． People living at higher altitude have lower possibility of dying from heart disease than those closer to sea level, even if they have factors that could increase their risk．"Residence in mountainous areas seems to have a 'protective effect' from heart disease," said Dr Nikos Baibas of the University of Athens．He and his colleagues suspect that the increased exercise from walking up mountainous area gives the heart a good workout and enables it to cope with lower levels of oxygen．
Researchers studied the health records and death rates of 1,150 Greeks who lived in three villages near Athens over 15 years．One village was 1,000 metres above sea level and the other two were in low-lying areas．Although men and women living in the mountainous village had higher blood pressure rates and other risk factors than people in the other villages, they had a lower rate of death from heart disease and other causes after a fifteen year follow-up．"The contrast was more evident among men than among women," Baibas added in a report in the Journal of Epidemiology and Community Health．Heart disease is one of the world's top killers．Smoking, high blood pressure, raised cholesterol levels, being overweight or obese and a family history of the illness increase the odds of developing the disease．
66．Among all the partners, __________ seemed to be the least interested in talking with the author.
A．the guy with glasses B．the middle-aged woman
C．the man in his computer chair D．the last man mentioned
65．The underlined word "disable" in Paragraph 2 means __________．
A．store B．close C．misuse D．copy