It’s true that quite a few most respected scientific authorities have confirmed that the world is becoming hotter and hotter. There’s also strong evidence that humans are contributing to the warming. Countless recent reports have proved the same thing. For instance, a 2010 summary about the climate science by the Royal Society noted that: “The global warming over the last half-century has been caused mainly by human activity.”
You may not believe that humans could change the planet’s climate, but the basic science is well understood. Each year, billions of tons of greenhouse gases are released into the atmosphere because of human activity. As has been known for years, these gases hold heat that would otherwise escape to space, wrapping the planet in an invisible (看不见的) blanket.
Of course, the earth’s climate has always been changing due to “natural” factors such as volcanic eruption or changes in solar, or cycles concerning the Earth’s going around the sun. According to the scientific research, however, the warming observed by now matches the pattern of warming we would expect from a build-up of greenhouse gas in the atmosphere – not the warming we would expect from other possible causes.
Even if scientists did discover another reasonable explanation for the warming recorded so far, that would give birth to a difficult question. As Robert Henson puts it: “If some newly discovered factor is to blame for the climate change, then why aren’t carbon dioxide and the other greenhouse gases producing the warming that basic physics tells us they should be?”
The only way to prove with 100% certainty that humans are responsible for global warming would be to run an experiment with two identical Earths – one with human influence and one without. That obviously isn’t possible, and so most scientists are careful not to state human influence as an absolute certainty.
小题1:In most scientists’ opinion, the global warming is mainly caused by ________.
A．solar activity
B．volcanic activity
C．natural factors
D．human factors小题2:The text is developed by ________.
A．giving typical examples
B．following the order of space
C．analyzing a theory and arguing it
D．comparing and finding differences小题3:The underline word “identical” in the last paragraph probably means ________.
A．totally different
B．exactly the same
C．extremely important
D．partly independent小题4:Which of the following is not the cause of climate change?
A．volcanic eruption
B．cycles concerning the Earth’s going around the sun
C．changes in solar
D．floods and droughts小题5:Which of the following can be the best title?
A．Are All the Scientists Really Scientific?
B．Where Is Global Warming Leading Us to?
C．Are Humans Definitely Causing Global Warming?
D．What’s the Relation of Global Warming and Greenhouse Gases?
小题1:D
小题2:C
小题3:B
小题4:D
小题5:C
题目分析：文章对人类是否对气候变暖这一理论进行了论述，表明是否是人类的影响尚且不能定论。
小题1:细节题。从第一段There’s also strong evidence that humans are contributing to the warming. Countless recent reports have proved the same thing.可知，绝大多数的科学家认为，全球气候变暖是由于人类的因素。故选D
小题2:推断题。文章对首先对一个普遍存在的理论进行分析，再引用一些专家的观点对这一普遍的理论进行辩论，故选C
小题3:推断题。从最后一段可知，如果要分析是否是人类造成的影响需要有两个完全条件一致的实验，一个有人类活动的地球，一个是没有人类活动的地球，对两个实验进行参照性的比较，显然这是不可能的，故选B
小题4:细节题。从文章第三自然段such as volcanic eruption or changes in solar, or cycles concerning the Earth’s going around the sun.可知，除了D答案外其余的都是气候变化的原因。
小题5:主旨题。文章对人类是否对气候变暖这一理论进行了论述，表明是否是人类的影响尚且不能定论，所以最好的标题是人类一定会造成气候变暖吗？故选C
点评：说明文是高考必考的文章体裁，出题的范围很广泛，新型科技类文体是比较受青睐的。学生在解答此类题目时应对整个文章做个大概的了解，对每一段的第一句话迅速的阅读，进而读题，在读题的过程中找出关键词在文章中进行定位，逐一作答。
