As the Arctic thaws，can science help to chart a sustainable path for the north?

          Last winter，parts of the Canadian Arctic basked in record­breaking warmth. In the town of Coral Harbour，at the mouth of Hudson Bay，temperatures rose above freezing for a few days in January for the first time ever.Across the Arctic，extreme climate conditions are becoming the norm，even as the region faces other profound changes，such as the growing political power of local people and the race to extract mineral resources (see page 172)．

          This  week，Nature  examines  how  these changes  are affecting scientific access to the north (see page 174)，and what scientists should do to keep Arctic development green (see page 179) and peaceful (see page 180)．Some are calling  for  international  regulations   to   safeguard  the environment as ship traffic increases (see page 157 )．Both research and development need to consider the views of local people，and scientists are learning how to do so (see page 182)．Locals can provide insight into environmental changes.

          There  is  a  long  tradition of international  scientific cooperation in the Arctic.That tradition must be preserved and expanded，even as nations in the region push forward with territorial claims under the UN Convention on the Law of the Sea. Countries should work together，perhaps through the Arctic Council，to ensure that researchers from all nations are allowed access to all parts of the Arctic Ocean.

At the same time，scientists should make their data available in public databases as soon as possible after collection.The far north is changing faster than anywhere else on earth，with potentially vast impacts on climate as carbonrich permafrost melts，and dark ground and water exposed by the retreating ice soak up more heat from the Sun.It is crucial that science keeps up.

          假设你是李华，你的英国朋友Peter来信向你咨询如何才能学好中文。请你根据下列要点写回信。

          要点：（1）参加中文学习班（2）看中文书刊、电视（3）学唱中文歌曲（4）交中国朋友

          注意：（1）词数100左右（2）可适当增加细节，以使行文连贯（3）开头语已为你写好

Dear Peter,

          I'm glad to receive your letter asking for my advice on how to learn Chinese well……

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Best wishes,

                                                                   Li Hua

—That was the reason ________ he gave up the plan. （   ）

          Mr.Jones woke early one morning.  It was a beautiful morning，so went to  the window and looked out.  He was surprised to see a neatly dressed，middle­aged professor,     worked in the  university near his house. He had grey hair and thick glasses，and was carrying      umbrella，a morning newspaper and a bag.  Mr. Jones thought that he must   ( arrive)  by the night train and decided to walk to the university instead of   (take) a taxi.

          Mr. Jones had a big tree in his garden，and the children had tied a long rope to one of its branches，so that they could swing on it.

Mr. Jones was surprised to see the professor stop and look      (care) up and down the road.      he saw that there was nobody in sight，he stepped into the garden (there was no fence)，put his umbrella，newspaper， bag and hat neatly on the grass and took hold of the rope. He pulled it hard      (see) whether it was strong enough to take his weight，then       (run) as fast as he could and swung into the air on the end of the rope.

          At last the professor stopped and continued on his way     the university，looking as quiet and correct as one would expect a professor to be.