题目内容：

Starving polar bears are eating one another in the Arctic. Flowers are blooming too soon and die. The ice caps are melting so fast that rising water levels will threaten coastal towns along Florida within several decades. These are just a few examples of the terrible consequences of climate change supported by a new analysis in Nature.

In the past three decades, average global temperatures have risen about 0. 6°C and are projected to jump by about 1. 7°C by the end of the century, says Cynthia Rosenzweig, who leads the Climate Impacts Group at NASA’s Goddard Institute for Space Studies at Columbia University in New York. “We’ve already seen that a relatively low amount of warming,” she says, “can lead to a broad range of changes. ”

The unnatural warming caused by man-made greenhouse gases, especially carbon dioxide produced by cars and coal-powered plants, brings trouble for entire ecosystems. In North America alone, scientists have identified 89 species of plants, such as the American holly that have flowered earlier in the spring. In Spain, apple trees bloom 35 days ahead of schedule in response to the higher temperatures. Other wildlife, like the insects that use certain plants for food and the birds that feed on the insects, must then move forward their seasonal stirrings(萌动) and mating（交配） patterns to survive.

To try to follow this time shift, some birds such as robins, the classic symbol of winter’s thaw(解冻时期), are returning to Colorado from their migrations some two weeks earlier than in years past. All these changes can throw a food chain in disorder. Some bird species that arrive before the insects reappear may starve to death.

“Around the world, plants and animals are waking up to an earlier alarm clock than they used to,” says Terry Root, a biologist from Stanford University.  

1.The underlined word “projected”(in Paragraph 2) probably means “____”.

A．forced

B．presented

C．indicated

D．predicted

2.According to the third paragraph, as a result of climate change ____ .

A．the warm weather wakes animals up earlier

B．certain trees bloom a season ahead of time

C．the birds need to change patterns of living

D．the American holly will flower in late spring

3.What can we know about robins according to the passage?

A．Farmers depend on them to tell the time.

B．They used to come back when spring came.

C．They used to predict the change of weather.

D．They usually migrate when seasons change.

4.What would be the best title for the passage?

A．Man is to blame for global warming

B．Great changes take place on Earth

C．Bird migration and climate change

D．Global warming changing nature’s clock