they range all the way across the Arctic,and as far south as James Bay in Canada.It is difficult to figure out a global population of polar bears as much of the range has been 2.

(poor) studied;however,biologists calculate that there are

about 20,000-25,000 polar bears worldwide.

Modern methods 3. tracking polar bear populations have been employed only since the mid-1980s,and are expensive 4. (perform) consistently over a large area.In recent years some Inuit people in Nunavut 5. (report) increases in bear sightings around human settlements,leading to a 6. (believe) that populations are increasing.Scientists have responded by 7. (note) that hungry bears may be congregating(聚集) around human settlements,leading to the illusion(错觉) that populations are 8. (high) than they actually are.Of 9. nineteen recognized polar bear subpopulations,three are declining,six 10.data. 答案与解析:

1.that 解析该空前后均为句子,且空格后面的句子是对空格前面的名词evidence的内容的解释说明,由此判断该空为同位语从句的引导词,表示陈述语气,故填that。

2.poorly 解析该空前后部分均为谓语成分hasbeenstudied,用副词修饰谓语部分,故填poorly。

3.of/for 解析该空前面为名词methods,后面为动词-ing形式tracking,故应填介词。用of表示所属关系,也可填介词for。

4.to perform 解析该空所在分句已有谓语动词are,故应填动词的非谓语形式。根据“be+adj.+todo”结构可知,应填toperform。

5.have reported 解析本句的时间状语为inrecentyears,是现在完成时的标志。根据语境,主语Inuitpeople与report之间为主动关系,且people为复数形式,故填havereported。 6.belief 解析该空前面有冠词a,应填名词,故填belief。

7.noting 解析该空前面为介词by,应填动词-ing形式,且scientists与note之间为逻辑上的主动关系,故填noting。

8.higher 解析该空后面有than,应填形容词的比较级形式,故填higher。

9.the 解析该空后面为名词短语,根据语境及空格前的of可知存在限定范围,故填the。

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(be) stable,one is increasing,and nine lack enough

10.are 解析根据并列谓语动词时态和语态一致原则,此处采用一般现在时和主动语态。故填are。

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