Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

It is common knowledge that the Internet, often called simply Net, is the largest network of computers in the world. It connects businesses, institutions and individuals. One of its main uses is communication, and electronic mail, or e-mail, is probably the most popular use of the Internet. Although the Net is widely used by people of all ages, many adults are now concerned about is possibly harmful effects on young people.

 example, chatting is a popular activity on the Net. Electronic chat rooms are Internet sites where people can communicate directly with one another. These chat rooms are quite popular with children. However, adults with inappropriate or illegal motives may also join chat rooms. Sometimes these adults try to arrange face-to-face meetings with unsuspecting victims. There have cases where children have been tricked by adults who pass them off as children and who give information that provokes to be entirely false.

Another cause of worry for parents is the huge amount of information accessible to users of the Internet. Not all information on the Net is accurate, and some deliberately misleading. In addition, parents worry that children may be exposed to harmful material. For instance, there are innumerable sites where explicitly violent or pornographic scenes are shown. Moreover, many organizations maintain hate sites that present racist or politically extreme views.

The Internet has tremendous potential for good, but it has also led to some serious questions about appropriate use. Where protection of their children is needed, parents should not hesitate to intervene. Unlimited freedom on the Net can lead to serious, sometimes dangerous, consequences.

 The author generally believes that children _____.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

On the fourth Thursday in November, in houses around the United States, families get together for a feast, or a large meal. Almost all families eat turkey and cranberry sauce for this meal, and have pumpkin pie for dessert. This feast is part of a very special day, the holiday of Thanksgiving.

In 1620 the Pilgrims made a difficult trip across the ocean from England. They landed in what is now Massachusetts. In England the Pilgrims had not been allowed to freely practice their religion. So they went to the New World in search of religious freedom.

The Pilgrims' first winter was very hard. Almost half the group died of cold, hunger and disease. But the Indians of Massachusetts taught the Pilgrims to plant corn, to hunt and to fish. When the next fall came, the Pilgrims had plenty of food. They were thankful to God and the Indians and had a feast to give thanks. They invited the Indians to join them. This was the first Thanksgiving.

Thanksgiving became a national holiday many years later because of the effort of a woman named Sarah Hale. For forty years Sarah Hale wrote to each president and asked for a holiday of Thanksgiving. At last she was successful. In 1863 President Lincoln declared Thanksgiving a holiday.

How much is Thanksgiving today like the Pilgrims’ Thanksgiving? In many ways they are different. For example, historians think that the Pilgrims ate deer, not turkey. The idea of Thanksgiving, though, is very much the same: Thanksgiving is a day on which we celebrate and give thanks.

When did the the Pilgrims make a difficult trip to across the ocean from England?

According to the passage, why do ants use different compounds a trail pheromones?

According to the passage, all of the following statements about plaque are true EXCEPT_________.

The passage most probable continues with a discussion of theories on

Read the following passage and mark the letter A, B, C, or D on your answer sheet

to indicate the correct answer to each of the questions.

The cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been "primed" by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed.

Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective.

Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

What does this passage mainly discuss?