EI Nino is the name given to the mysterious and often unpredictable change in the climate of the world. This strange 47 happens every five to eight years. It starts in the pacific Ocean and is thought to be caused by a failure in the trade winds(信风), which affects the ocean currents driven by these winds. 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℃(degrees centigrade).

    The warning of the ocean has far-reaching effects. The hot, humid (潮湿的)air over the ocean causes severe 49 thunderstorms. The rainfall is increased across South America, 50 floods to Peru. In the West Pacific, there are droughts affecting Australia and Indonesia. So while some parts of the world prepare for heavy rains and floods, other parts face drought, poor crops and 51 .

    EI Nino usually lasts for about 18 months. The 1982-83 EI Nino brought the most 52 weather in modern history. Its effect was worldwide and it left more than 2,000 people dead and caused over eight billion pounds 53 of damage. The 1990 EI Nino lasted until June 1995. Scientists 54 this to be the longest EI Nino for 2,000 years.

    Nowadays, weather experts are able to forecast when an EI Nino will 55 , but they are still not 56 sure what leads to it or what affects how strong it will be.

    其选项如下：

    A) estimate;

    B) strength;

    C) deliberately;

    D) notify;

    E) tropical;

    F) phenomenon;

    G) stable;

    H) attraction;

    I) completely;

    J) destructive;

    K) starvation;

    L) bringing;

    M) exhaustion;

    N) worth;

    O) strike

    解题方法

    一、辨析词性

    把十五个选项按词性分别归入名词、动词、形容词、副词等类别。

    纵观样题和试题，我们知道15个词汇都属于最重要的四类实词。我们要学会每种词汇的基本搭配和基本用法。

    辨性要注意下面几点。

    1.遇到动词进行二次分类：确定时态，确定是第三人称单数还是非第三人称单数;但应注意动词+ed型的有两种可能性，动词或形容词;遇到名词要确定单数还是复数。英语四级分数分布

    2.不认识的单词，看后缀。构词法中，前缀表明意思，后缀表明词性。所以看一个词的后缀，往往能大致分出词性。

    3.词性一时无法确定的，暂时搁置，不必纠缠，影响全局。

    4.作出相应的标记。可直接用自己最清楚的符号清楚标在每个词前后。不清楚的都标问号。

    以试题为例辨词性

    A) estimate; B) strength;

    C) deliberately; D) notify;

    E) tropical; F) phenomenon;

    G) stable; H) attraction;

    I) completely; J) destructive;

    K) starvation; L) bringing;

    M) exhaustion; N) worth;

    O) Strike

    名词：B,F,H,K,M

    (B的后缀th, H、K、M的tion都是名词后缀)

    谓语动词：A,D,O

    (A的-ate极可能是动词，D的-fy为动词后缀)

    非谓语动词：L(-ing结尾)

    形容词：E, G, J

    (E的-cal, G的able, J的tive是形容词后缀)

    副词：C和I(ly加在形容词后为副词后缀)

    注意：即使从没见过，也想办法看能否判断其词性，词的性质有时比词义还重要。词的性质并不总是固定的，有些不认识的或无法确定的，如N) worth (adj./n.)，可先搁置，不要过度纠缠。 

(责任编辑：田学江)