History of agriculture. Since the 1800s, science and technology have helped make agriculture more and more productive in three main ways

Since the 1800s, science and technology have helped make agriculture more and more productive in three main ways. They have (1) provided farmers with labour-saving technologies; (2) produced improved plant varieties and breeds of livestock; and (3) developed new agricultural chemicals.

Labour-saving technologies. Steam-powered tractors were developed in the mid-1800s, but they were expensive and difficult to operate. The first all -purpose gasoline-powered tractors appeared in the 1920s. They gradually replaced work animals and steam-powered machines on almost all farms. In Japan and several European countries, most farms had electric power service by the mid-1930s. Today, farmers use electric motors to run milking machines, irrigation pumps, and many other farm machines. Farmers also use electric power to operate electronic and automated equipment. This equipment includes devices that fill feeding troughs or collect and grade eggs automatically.

Many farmers use computers to aid in farm operations and to keep track of finances. Using the Internet, farmers may make use of data provided by agricultural colleges or other information centers.

Plant and livestock breeding. During the mid-1800s, an Austrian botanist and monk named Gregor Mendel discovered the principles of heredity. Mendel thus laid the groundwork for genetics – the science that explains how characteristics are inherited. The development of genetics has made it possible to breed plants and animals scientifically.

Since the early 1900s, plant breeders have developed a great number of hybrid crops that produced unusually high yields. The new varieties were intended mainly to help various poor nations, such as India and Мехico, increase their food supply. This effort proved so successful that it has been called the Green Revolution.

Livestock breeders have introduced many improved lines since early 1900s. Nutrition specialists have developed better livestock feeds, and veterinarians have improved methods of health care. All these advances continue to make livestock more and more productive.

Agricultural chemicals. Almost since the beginning of agriculture, farmers have used various substances to enrich the soil and to kill insect pests. For example, they have used wood ash and manure as fertilizers since prehistoric times. Since the beginning of modern chemistry in the late 1700s, scientists have produced many kinds of synthetic chemicals for use in agriculture. These chemicals include (1) fertilizers; (2) insecticides; (3) herbicides, or weedkillers; and (4) chemicals to control plant and animal diseases. All these chemicals have helped increase farm production greatly. However, improper or excessive use of these chemicals can be dangerous and cause damage to the environment. In many countries state laws limit such practices and prohibit the use of chemicals that have been proved harmful.

Вариант № 4

I. Перепишите предложения, определите в каждом из них видовременную форму и залог глагола- сказуемого, переведите предложения на русский язык.

1) The factories are provided with new machines.

2) Several parts of the machine are being reconstructed by the mechanic now.

3) He will send the letter tomorrow.

4) Several jobs were offered to me by the manager.

5) Our experiments will have been finished by the end of the year.

II. Перепишите предложения и переведите их на русский язык, найдите и подчеркните инфинитив и причастие, определите функцию инфинитива и причастия в предложении.

1) The students must work on the farms.

2) Changed into his uniform, he looked younger and slimmer.

3) What we really want is a good critical article revealing our drawbacks.

4) To solve this problem is very important for agriculture.

5) To ski in the forest gives me pleasure.

6) He was playing tennis the whole evening yesterday.

7) He worked hard in order to improve his pronunciation.

8) To write the report he read a lot of literature.

III. Перепишите предложения, найдите и подчеркните объективный и субъективный инфинитивные обороты, переведите на русский язык.

1) He hated people to argue about trifles.

2) The book is said to be very popular.

3) He is not sure to change his opinion.