[典例]
The polar bear is found in the Arctic Circle and some big land masses as far south as Newfoundland. While they are rare north of 88°, there is evidence 61 they range all the way across the Arctic, and as far south as James Bay in Canada. It is difficult to figure out the global population of polar bears as much of the range has been 62 (poor) studied; however, biologists calculate that there are about 20,000—25,000 polar bears worldwide.
Modern methods 63 tracking polar bear populations have been employed only since the mid-1980s, and are expensive 64 (perform) consistently over a large area. In recent years some Inuit people in Nunavut 65 (report) increases in bear sightings around human settlements, leading to a 66 (believe) that populations are increasing. Scientists have responded by 67 (note) that hungry bears may be congregating (聚集) around human settlements, leading to the illusion(错觉) that populations are 68 (high) than they actually are. Of 69 nineteen recognized polar bear subpopulations, three are declining, six 70 (be) stable, one is increasing, and nine lack enough data.

语篇解读 本文是一篇说明文。文章介绍了北极熊的地理分布以及对其种群数量的估算与研究现状。
61. that ［考查同位语从句。分析句子结构可知，所填词引导同位语从句，解释说明evidence的具体内容，从句中不缺少成分且意义完整，故用that引导。故填that。］
62. poorly ［考查词性转换。修饰动词studied应用poor的副词形式。故填poorly。］
63. of/for ［考查介词。a method of/for doing sth意为“做某事的方法”。故填of/for。］
64. to perform ［考查非谓语动词。此处是“主语＋be＋形容词＋动词不定式”结构，动词不定式用主动形式表示被动含义。故填to perform。］
65. have reported ［考查动词的时态和主谓一致。根据句中的时间状语in recent years可判断用现在完成时，主语为复数。故填have reported。］
66. belief ［考查词性转换。根据空格前的不定冠词a可知，此处应填believe的名词形式，belief意为“看法，信念”。故填belief。］
67. noting ［考查非谓语动词。介词后接动词时，应用动词-ing形式。respond by doing sth意为“通过做某事回应”。故填noting。］
68. higher ［考查形容词比较级。根据空格后的than可知，此处应用high的比较级形式。故填higher。］
69. the ［考查冠词。此处特指确认的19个亚种群，故用定冠词the。故填the。］
70. are ［考查动词的时态和主谓一致。此处陈述客观事实，应用一般现在时；six指代six polar bear subpopulations，谓语动词应用复数形式。故填are。］