VOA慢速英语:US Lets Farmers Plant Biotech Sugar Beets, With Conditions

1.The United States Department of Agriculture has given farmers permission to plant genetically engineered sugar beets with some conditions.

permission to plant,是动词不定式做后置定语

不定式在句中做定语通常做后置定语，即放在被修饰名词或代词后。它通常有以下几种用法：

(一)不定式常可用来修饰物，表示要做某事。

如：1)The next train to arrive was from NewYork.下一列到站的火车是从纽约开来的。

2)I have nothing to say on this question.在这个问题上，我没有什么话要说。

3)We are looking for somewhere to live.我们正在找一个地方住。

(二)不定式还可用来修饰人。

如：1)He was the first guest to arrive.他是第一个到达的客人。

2)Miss Brown was the next person to rise to speak.布朗小姐是下一个起来发言的人。

3)He was a brave man to do what he did.他是个勇者才有这样的行为。

(三)很多特定的名词后也可用不定式做定语，这样的名词常用的有：way，time，reason，chance，opportunity，need，wish，effort，right，ambition等。

如：1)It's time for you to get up and go to school.你该起床去上学了。

2)There is no reason to doubt his word.没有理由怀疑他的话。

3)They have now an opportunity to go abroad to study further.他们现在有机会出国深造。

(四)某些动词或形容词后可接不定式时，它相应的同根名词也常用不定式做定语。

如：1)He made an attempt to learn English well.他试图学好英语。(attempt to do sth)

2)His ability to get on with people is his chief advantage.他能和人相处是他的主要优势。(be able to do sth)

3)I don't trust his promise to come for a visit.我不相信他来访的诺言。(promise to do sth)

4)Her anxiety to succeed led her to work hard.她迫切想成功，这促使她努力工作。(be anxious to do sth)

2.The action lets growers plant the genetically changed sugar beets if they obey certain rules.

certain用法归纳

1)表示“一定”或“确信”，通常用作表语，注意：

(1) 后接不定式时，表示说话人的看法，意为“一定会”、“肯定会”。如：

He’s certain to succeed (come). 他一定会成功(来)。

【注】这类句型可作以下转换：

It’s certain that he will succeed (come).

(2) 后接“of＋名词(或动名词)”或后接 that /whether从句等，表示句子主语的信念，意为“确信”、“自信”。如：

He is certain of success (winning). / He is certain thathe can succeed (win). 他确信会成功(赢)。

【注】有时后接介词 about。如：

I’m quite certain about it. 我对此很有把握。

2)表示“某一”、“某些”，通常用作定语。如：

A certain Mr Smiths called this afternoon. 有个叫史密斯先生的人今天下午来过电话。

He was absent for certain reasons. 由于种种原因他没有出席。

3)用于 for certain, 意为“肯定地”、“确切地”等。如：

I can’t say for certain where he lives. 我不敢肯定地说他住在什么地方。

4)用于 make certain, 意为“弄清楚”、“弄得有把握”。如：

They made certain (that) they weren’t late. 他们有把握不迟到。

Arrive early at the cinema to make certain of getting aseat. 早点去电影院以便能弄个座位。