The agricultural revolution in the nineteenth century involved two things：the invention oflabor-saving machinery and the development of scientific agriculture．Labor．saving machinerynaturally appeared first where labor was SCarCe．“In Europe”，said Thomas Jefferson，“the ob．ject is to make the most of their land，labor being abundant；here it is to make the most of ourlabor，land being abundant．”It Was in America，therefore，that the great advances in nine-teenth-century agricultural machinery first came．At the opening of the century，with the excep-tion of a crude plow，farmers could have carried practically all of the existing agricultural imple-ments(农具)on their backs；by 1860，most of the machinery in use today had been designedin an early form．The most important of the early inventions was the iron plow．As early as 1790 Charles Newbold of New Jersey had been working on the idea of a cast-iron plow and spent hisentire fortune in introducing his invention．The farmers，however，would have none of it，clai-ming that the iron poisoned the soil and made the weeds grow．Nevertheless，many people devot-ed their attention to the plow，until in 1869 James Oliver of South Bend，Indiana，turned out thefirst chilled—steel(冷淬钢)plow．

根据以上内容，回答下列各题。

What is the main topic of the passage?

1．广告正走进人们的生活。

2．广告能提供我们大量的信息。

3．然而，广告不一定都真实。

__________.

__________.

__________.

A．See you this evening

B．Ive gotta run

C．See you again

D．won’t be back for supper

E．Ill go to the office

F．Take care

G．Don’t worry

H．Ill just take the subway

Gary：Dear，I have to go to the office early today．Can you take Sally to school?Ada：Sure．Want me to give you a ride?

Gary:N0，forget it． ____56____ ．it’s very quick．Ill pick Sally up this afterrnoon．You can just come home after work．

Ada：Ok．Oh，I almost forgot．I probably 57．Ive made an evening appointment

with Mr．Steven to talk about our next project．

Gary：Oh，I see．____58____．Hurry Sally up a little．She hasnt even had her breakfast yet．Ada：Ok． ____59____．Love you，honey．

Gary：I love you，too．____60____．

根据以上内容，回答下列各题。

__________.

__________.

The application of infrared scanning technolgy to agriculture met with some difficul-ties due to_________．

Plants will emit an increased amount of heat when they are_________

Farmers can save a considerable amount of pesticide by_________．

Even plants can run a fever，especially when they’re under attack by insects or disease．But unlike humans，plants Can have their temperature taken from 3,000 feet away—straightup．A decade ago，adapting the infrared(红外线)scanning technology developed for militarypurposes and other satellites，physicist Stephen Paley came up with a quick way to take thetemperature of crops to determine which ones are under stress．The goal was to let farmers pre-cisely target pesticide(杀虫剂)spraying rather than rain poison on a whole field，which in-variably includes plants that don’t have pest(害虫)problems．

Even better．Paley’s Remote Scanning Services Company could detect crop problems be-fore they became visible to the eye．Mounted on a plane flown at 3，000 feet at night，an infra-red scanner measured the heat emitted by crops．The data were transformed into a color-codemap showing where plants were running“fevers”．Farmers could then spot-spray，using 50 to70 percent less pesticide than they otherwise would．

The bad news is that Paleys company closed down in 1984，after only three years．Farm,ers resisted the new technology and long-term backers were hard to find．But with the　renewedconcem about pesticides on produce，and refinements in infrared scanning，Paley hopes to getback into operation．Agriculture experts have no doubt the technology works．“This techniquecan be used on 75 percent of agricultural land in the United States"，says George Oerther ofTexas A&M．Ray Jackson，who recently retired from the Department of Agricuhrue，thinks re-mote infrared crop scanning could be adopted by the end of the decade．But only if Paley findsthe financial backing which he failed to obtain 10 years ago．

根据以上内容，回答下列各题。

In order to apply pesticide spraying precisely，we call use infrared scanning to _________.