综合解题
将选项分类之后，就得从文章中来寻找对应的线索了。选项与文章匹配的因素有两个，第一是词性，第二是词义。所以在读文章时，要通过各种手段来确定空格的词性与意义。
(一)确定词性，确定选项的选择范围
1)关于动词的判断
前后都是名词短语，中间是动词 。
根据一句(包括从句)有且只有一个谓动的原则，其它地方如无谓语动词，则需要谓语动词;反之则不需要谓语动词。
Nowadays, weather experts are able to forecast when an El Nino will 55 , but.
(will后面必然是原形动词，一起构成谓语)
55. O strike
Scientists 54 this to be the longest El Nino for 2,000 years.
(此句后只有一个to be，是非谓语动词，故空格必为谓语动词;且空格前后均为名词性，也基本确定它是动词。)
54. A estimate
一个完整的句子之后再跟逗号，后面一般是非谓语动词短语。
The rainfall is increased across South America, 50 floods to Peru.
(前面是一个完整的句子，逗号后跟的，一般是非谓语动词短语。此题选项中非谓语动词只有一个，故直选之。)
50. L bringing
2)其它词的判断
形容词或名词修饰名词，限定词(the, this, that, a, my之类)后必有名词
This strange 47 happens every five to eight years.
47. F phenomenon
The hot, humid (潮湿的) air over the ocean causes severe 49 thunderstorms.
49. E tropical
El Nino usually lasts for about 18 months. The 1981-83 El Nino brought the most 52 weather in modern history.
(前面是最高级的修饰语，自然是形容词。)
52. J destructive
副词修饰形容词或动词
…, but they are still not 56 sure what leads to it or what affects how strong it will be.(修饰形容词sure, 当为副词)
56. I completely
谓语动词前有名词主语
This strange 47 happens every five to eight years.
(happens是谓语动词，也可知前面为名词短语，缺一个核心名词。)
47. F phenomenon
介词后面必有名词
As the trade winds lessen in 48 , the ocean temperatures rise, causing the Peru current flowing in from the east to warm up by as much as 5 °C.
(在介词in的后面，当为名词无疑，此处整个短语来修饰lessen减少，当为在某个方面减少。)
48. B strength
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