二、疑难解析

1. It is on this arable land that the famers produce food for the whole population of China.

农民们正是在这些可耕地上为全国人民生产各种粮食。

[问]如何理解这个句子结构?

[答]这是个强调句，，其结构为：It is (was)+被强调部分+that/who-从句，被强调部分可以是句子的主语、宾语、状语等，如果被强调部分是物，从句用that引导，如果指人，则可用that或who来引导从句。课文第三段还有一个强调句。又如：

It was they who (that)helped me in the street this morning. 今天上午就是他们在街上帮了我。

It was this morning that they helped me in the street. 他们是今天上午在街上帮我的。

Who was it that taught them French yesterday? 昨天教他们法语的是谁?

What was it that the new teacher taught them yesterday? 昨天新老师教他们的是 什么?

2. To make as much use of the land as possible. two or more crops are planted each year where possible. 为了更充分地利用土地资源，在可能种植两种或两种以上作物的地方种植不同的作物。

[问]不定式短语为什么放在句首?怎样理解as possible 和where possible?

[答]不定式作目的状语可位于句首，起强调作用，此外i norder to 和so as to 都可引导目的状语，但so as to 不能位于句首。如：

(In order )to pass the exams, he did his lessons till late at night.

为了通过考试，他复习功课直到深夜。

此句可改为：He did his lessons till late at night so as to pass the exam. 句中的make use of 是一个短语，意为：“利用、使用”，如：

We should make full use of time in our study. 我们在学习中应充分利用时间。

It is very important for us to make good use of water. 好好利用水资源是很重要的。

句中的as much ... as possible 意为：“尽可能多地……”， much 后接不可数名词，若为可数名词，则用many来修饰。又如：

Please give him as muvh help as possible. 请尽可能多地买了书。

句中的where possible 是一种省略形式，在句中作地点状语，相当于where it is possible ，连词if，when， while， until等都可用于这种省略句。例如：

I will pay you a visit when (I am)free. 我有空时会来看你的。

Tell the manager immediately about it if (it is )necessary. 如有必要，迅速把这事儿告诉经理。

3. This saves time and allows famers to grow an extra crop in each season. 这就节约了时间允许农民可以在每个季节里种植一种额外的作物。

[问]allow 和let的含义和用法有什么不同?

[答]二者均可作“允许”解，但各有侧重;allow重在“允许”或“容许”，也可表示客气的请求，常用于allow sb. to do sth. 或allow doing sth. 结构中。例如：

He allowed me to take his dictionary. 他允许我拿走他的词典。

Will you allow me to use your bike?我可以用你的自行车吗?

We don't allow smoking here. 我们不允许在这儿抽烟。

而let作“允许”或“让”解，主要用于口语，一般可与allow互换。作“允许”解时，常暗含“听任”“默许”之意。注意： let之后作宾补的不定式不带to， 且不可用于被动语态，而allow则相反。例如;

Please let me walk with you (=Please allow me to walk with you. ) 我(请允许我)跟你一起走。

4. It is from the early 1990s that scientists started to develop new techniques to increase agricultural production without harming the environment. 科学家开始发展研究既提高农业产量又不破坏环境的新技术是在二十世纪九十年代。

[问]该句中develop是什么意思?介词without有什么用途?

[答]develop 意为：发展，发达，发扬，发育，进步，逐步生长，逐步显示出来”等。如：

Plants develop from seeds. 植物由种子发育而成。

Several industries are developing in this area. 几种工业正在这个地区发展。

Some children develop more slowly than others. 有的儿童比其他的儿童发育得慢。

Fresh air and exercise develop healthy bodies. 新鲜空气和运动能使身体健康。

He developed the photo graphs which he had taken. 他冲洗了他拍摄的胶卷。

developing 意为：“发展中的”， developed意为“发达的”，如：

China is a developin country while Japan is a developed one. 中国是个发展中的国家， 而日本是个发达的国家。

介词without 表示“不，没有”， 后接名词、代词或-ing形式，在句中用做状语、表语或定语，如：

She day passed without seeing me. 她从我身边走过而没有看见我。

They never meet withour quarreling. 他们一见面就要吵嘴。

Future agriculture should depend on high technology as well as traditonal methods. 未来的农业将依靠高科技和传统的方法。

[问]as well 和as well as有什么不同?

as well意为： “还;也”， 相当于too， 通常位于句末。 如：

He gave me advice, and money as well. 他给我忠告，也给我钱。

She went there as well. 她也去了那儿。

as well as 与as well 同意，但常用来连接两个并列成分，可译为：“除……之外;和”。强调的重点在第一个成分。 如果连接的两个并了成分作主语，谓语动词的数和第一个成分一致。 如：

He gave me money as well as advice. 她除了给我忠告外，还给我钱。

You as well as I are right. 我是对的，你也是对的。

5. Not only food production is important but also taking care of the environment. 不仅食物生产很重要，保护好环境也同样重要。

[问]怎样理解这个句子结构?

[答]此句相当于：Not only food production but also taking care of the environment is important. 并列连词not only ...but also...意为：“不仅……，而且……”，连接两个并列的主语food production 和taking care of the environment.

not only... but also ...也可连接两个并列的谓语、宾语、表语、状语等，还可连接两个并列的句子，所强调的重点是后面的一个。有时可省略also。又如：

She not only sings well but (also)dances beautifully. 她不但歌唱得好，而且舞也跳得很优美。

He was not only a successful writer but (also)the greatest poet of his time.他不但是一位成功的作家，而且 他啊那个时代最伟大的诗人。

He is famous not only in China but in the whole world. 他不仅誉满中国，而且誉满全世界。

当not only ...but also...连接两个主语时，谓语动词应采取“就近一致”的原则，与后面哪个主语保持人称和数的一致。如：

Not only the students but also the teacher is pleased. 不仅同学们高兴，老师也高兴。

Not only he but also you are going there. 不仅他，而且你也要去那儿。