Đề thi học kỳ 2 môn Tiếng Anh lớp 11 trường THPT Thanh Ba, Phú Thọ năm học 2016 - 2017 có đáp án

Before the telephone invented by Alexander Graham Bell in 1876, it was hard for people (26)____over long distances. They wrote letters to each other. It could take days or even weeks for letters to be (27)____Then people learned how (28)____telegraph messages. The messages traveled as electric signals that represented a code of dots and dashes. An operator on the other end converted the dots and dashes into a regular message. Bell’s first telephone call went over the same wires used for telegraph messages. As the telephone became (29)____and more popular, it largely replaced the telegraph. Today, our huge telephone network does many things besides carrying telephone calls. It sends copies of letters and pictures from one machine to another, called a (30)____machine.

Scientists often divide resources into two groups: renewable and non– renewable. When a resource is used, it takes some times to replace it. If the resource can be replaced quickly and easily, it is called renewable. If it cannot be replaced quickly and easily, it is non-renewable. All fossil fuels are non-renewable resources. Solar energy, air, and water are usually called renewable because there is an unlimited supply. However, this definition may change if people are not careful with these resources. The amount of solar energy that reaches the earth depends on the atmosphere. If the atmosphere is polluted, the solar energy that reaches the earth may be dangerous. If humans continue to pollute the air, it will not contain the correct amounts of these gases. Many resources are limited and non- renewable, and many are in danger of pollution. As a consequence, resources must be conserved and the environment protected. Conservation must become an important part of everyone’s life.