1. 阅读下列短文，从每小题所给的 A、B、C、D 四个选项中选出最佳选项。

"The world's oceans are slowly getting more acidic," say scientists. The researchers from California report that the change is taking place in response to higher levels of carbon dioxide in the atmosphere.

The lowering of the waters' PH value is not great at the moment but could cause a serious threat to current ocean life if it continues, they warn. Ken Caldeira and Michael Wickett, from the Lawrence Livermore National Laboratory, report their concerns in the journal Nature.

Increasing use of oil fuels means more carbon dioxide is going into the air, and most of it will eventually be absorbed by seawater. Once in the water, it reacts to form carbonic acid. Scientists believe that the oceans have already become slightly more acidic over the last century.

These researchers have tried to predict what will happen in the future by combining what we know about the history of the oceans with computer models of climate change. "This level of acidity will get much more extreme in the future if we continue releasing COZ into the atmosphere," said Dr Caldeira. "And we predict the amount of future acidity will exceed(超过) anything we have seen over the last several hundred million years, let alone perhaps after rare disastrous events such as asteroid impacts. "

However, it is not absolutely clear what that means for ocean life. Most organisms live near the surface, where the greatest pH change would be expected to occur, but deep-ocean life forms may be more sensitive to PH changes. Coral reefs and other organisms whose shells contain calcium carbonate(小行星) may be particularly affected if the water's acidity levels keep going up, the team predict. They could find it much more difficult to build these structures in water with a lower PH.

In recent years some people have suggested storing carbon dioxide from power stations in the deep ocean as a way of dealing with global warming. But Dr. Caldeira said that such a strategy should now be re-considered. "Previously, most experts had looked at ocean absorption of carbon dioxide as a good thing—because in releasing CO₂ into the atmosphere we warm the planet, and when CO₂, is absorbed by the ocean, it reduces the amount of greenhouse warming. "

1. （1） According to Dr. Caldeira, _________.

   A . ocean absorption of carbon dioxide is a good thing B . more oil fuels will be used in the near future C . scientists may predict climate changes with computer models D . the future situation of the amount of acidity is extremely serious
3. （2） If the water's acidity level keeps rising, _________.

   A . ocean life whose structures contain calcium carbonate may be affected B . the waters' PH value will become higher and higher C . organisms living near the surface are more sensitive to pH changes D . some disastrous events will occur more often than before
5. （3） What does the underlined word "acidic" probably mean?

   A . 污染的 B . 酸的 C . 复杂的 D . 温暖的
7. （4） How did researchers predict what will happen in the future?

   A . They studied many reports in the journal Nature B . They tested the carbon dioxide in the atmosphere C . They combine what they know about the history of the oceans with computer models of climate change D . They thought ocean absorption of carbon dioxide was a good thing
9. （5） The purpose of this passage is to _________.

   A . show people the findings of a research team B . inform people of how acid the ocean is now C . introduce Dr. Caldeira and his team's research D . warn people of the higher level of CO₂