A
Antarctic seabirds are breeding (繁殖) later，because thinner sea ice is causing their food supplies to decline，a new study says. The birds，which nest in East Antarctica，have delayed their spring arrival by an average of nine days and egglaying by an average of two days over the past 50 years，according to polar researchers from the French National Center for Scientific Research in Villiers en Bois, France. Study authors Christophe Barbrand and Henri Weimerskirch attribute this later breeding activity to decrease in sea ice caused by climate change.
The researchers say the disappearing sea ice，combined with a longer seaice season, has interfered with the birds’ breeding cycle by reducing the amount of krill (磷虾) and other prey (猎物) available in early spring in Antarctica. Because Antarctica’s seasons are opposite those in the Northern Hemisphere，spring on the icy continent begins in October.
The study is based on data collected at seabird colonies between 1950 and 2004 in Adélie Land, on the eastern edge of the frozen continent.
The findings were published in the journal Proceedings of the National Academy of Sciences.
Of the nine species studied, some arrived up to 30 days later than they had in previous years.
Despite much later arrivals, the birds are laying their eggs at pretty much the same time as they had in the past. In the most extreme cases, birds were laying their eggs an average of 3.7 days later in the season than they were 50 years ago.
【解题导语】 本文主要介绍了生活在南极洲东部的海鸟推迟繁殖的原因。
1．What is the passage mainly about?
A．Seabirds are breeding later in East Antarctica.
B．The amount of krill in the ocean has decreased.
C．The weather in Antarctica has changed.
D．The spring in Antarctica is beginning later.
A 解析：主旨大意题。纵观全文，文章主要介绍的是现在生活在南极洲东部的海鸟的繁殖期由于气候变化而延后。
2．In which of the following months is it autumn in Antarctica?
A．October. B．September.
C．November. D．June.
D 解析：推理判断题。根据文章第二段第二句可推知南极6月应是秋天。
3．How many kinds of seabirds were studied by the researchers?
A．Two. B．Five.
C．Nine. D．Thirty.
C 解析：细节理解题。根据文章第五段可知研究了九种鸟。
4．What does the underlined word “attribute” in Paragraph 1 mean?
A．It means “contribute”. B．It means “cause”．
C．It means “owe”. D．It means “devote”．
C 解析：词义猜测题。研究者认为这种推迟的生育行为是由于气候变化导致的海冰减少而引起的。attribute...to...“把……归因于……”，C项与之相符。
