近年来，北极地区成为各国争夺的“新战场”，北极问题的焦点是北极航道权益的竞争。北极航道是连接太平洋北部和大西洋北部的重要通道，包括绕过西伯利亚北部的东北航道和绕过加拿大北部的西北部航道。近年来，北极地区逐渐成为各国争夺的“新战场”的原因是（   ）

根据句子意思，从方框中选用恰当的词或短语填空。

____ My school has          weeks off in the summertime than Daniel’s school.
____ Xi Wang          a healthy young giant panda and weighed 35 kilograms.
____ Daniel is very clever, but he          shows off.
____ This CD-ROM helps you learn English          testing your knowledge of English grammar and vocabulary.
____ To tell you the truth, sometimes I          my cousin Shirley.
____ You can’t sneeze and keep your eyes open         .
____ Later, the government          it was a very serious problem and took action to reduce the pollution.
____ The spirit of the Olympics is “Swifter, higher,         .”

一种商品的价格先提高20％，再打九折，现价与原价相比（   ）。