句子·剖析·拓展

Scientists have tried many ways to solve the problem and in China,a mass campaign has been started to help solve it.

科学家已经采用许多方法来解决沙尘暴的问题，在中国，一场大规模的整治沙尘暴战役开始了。

　　【剖析】 1）本句是个并列句，由and连接。to solve this problem作目的状语。第二个分句为被动结构。

　　2）动词try意思为"尝试；试用；试验"，后面接名词、代词或短语。try to do sth.意思是 "尽力/试图做某事"，但未必成功； try doing sth.意思是"试着做某事"；try on意思是"试穿"，均为try的常用短语。

　　【拓展】 及物动词start在本文中的意思为"使开始"。它还有"发动(汽车)；开创(事业)；创办(报纸)；开始做某事"等意思。短语to start with意为"首先；起初"，start with相当于begin with，意为"以......开始"。

They are often so thick that you cannot see the sun,and the wind is sometimes strong enough to move sand dunes.

沙尘暴常常是浑浊不堪，导致你看不见太阳，而且大风有时很强劲，连沙丘都被吹跑了。

　　【剖析】 本句为并列句，由and连接。第一个分句是so...that...短语构成的句子，that从句表结果。第二个分句中的enough to do结构意思为"足以到......的程度"，enough之后是不定式作目的状语。

　　【拓展】 so...that...意思为"如此......以致......"，在这里引导结果状语从句，与such...that是同义短语。so后接形容词或副词。such后接名词或代词。so在两种情况下会使用名词，一种是"so+adj.+a/an+可数名词单数"，另一种是"so+many/much/few/little(少量)+名词(many/few后接可数名词复数，much/little后跟不可数名词)"。

"To have been caught in a sandstorm was a terrible experience," he said."There was nothing to be done.

他说"被困在沙尘暴中是一件很恐怖的事情。什么也干不了（即:一点办法都没有）"。

　　【剖析】 1）此处"To have been caught in a sandstorm"为不定式的完成式作主语。不定式作主语常用it作形式主语，真正的主语不定式结构放到后面，构成句型It is/was+adj./n.(+for sb.)+to do sth.。本句可改写为It was a terrible experience to have been caught in a sandstorm.

　　2）to be done不定式短语主动态作定语。

　　3）注意There was nothing to be done.(毫无办法，一点办法也没有)和There was nothing to do.(无所事事)两个句型意思的区别。

Sandstorms in China appear to have increased in recent years as a result of "desertification".

因"荒漠化"越发严重，中国近年来发生沙尘暴的次数明显增加了。

　　【剖析】 1）本句是个简单句，appear为连系动词，紧随其后的to have increased作表语。"as a result of desertification"表原因。

2）to have increased为不定式完成式，它表示的动作发生在主要动词appear所表示的动作之前。不定式的完成形式经常与appear，seem，happen，pretend等动词连用。

【拓展】 连系动词appear意思为"好像、似乎"后面接形容词、名词或动词不定式。