题目内容：

The “swim-with-dolphins” tourist industry is becoming more popular every year. After all, it can cost a large amount of money to have this kind of holiday experience. So tour operators try to place eager swimmers as near as possible to the dolphins by trying to predict where the dolphins will be.

Research has shown that while dolphins can move away if they do not want to interact (交流） with human swimmers, they do not like it at all if the swimmers slip into the water directly on top of them or if humans are in their path of travel. However, if swimmers enter the water to one side of them, the dolphins do not avoid the swimmers to the same extent.

In all cases, the dolphins seem to have become more sensitive to the presence of the swimmers. For dolphins, swimming amongst or with humans is not necessarily a high priority. This research has shown that only 19% of any group of dolphins will participate in interaction. Young dolphins are the most likely to interact; they do seem curious about being with humans. It is believed that they see humans as “entertainment” and that the interaction is a new and unusual experience for them.

It is frequently asked whether “swim-with-dolphins” tourism should be discontinued. The advice is that dolphins should be given enough periods of time throughout the day when they are not exposed to tourism. Permitted interactions should not be too disturbing to the dolphins since there could be mothers and calves (幼崽） present in dolphin groups. There should also be educational campaigns about the creatures and what is likely to cause danger to them.

It is not easy to explain to someone that they cannot fulfill their lifelong dreams because the dolphins are resting, or that a mother dolphin and calf are in the area. But if we are to enjoy these remarkable animals and not just use them for our entertainment, then we must carefully monitor the “swim-with-dolphins” industry worldwide.

1.What makes “swim-with-dolphins” tourism popular?

A. The local government’s encouragement.

B. The improvement of people’s living standard.

C. The increasing number of tourists.

D. The high profits of the industry.

2.Why are young dolphins more likely to swim with humans?

A. They do this out of curiosity.

B. They like humans better.

C. They are less sensitive.

D. They prefer new things by nature.

3.What does the author suggest the “ swim-with-dolphins” industry do in Paragraph 4?

A. Avoid interaction with young dolphins.

B. Strictly limit the expansion of the industry.

C. Make people know the hidden threat to dolphins.

D. Expose dolphins to tourists only in the daytime.

4.What can be inferred from the last sentence of the passage?

A. The industry has been a hot topic worldwide.

B. The industry aims to bring happiness to humans.

C. The industry enables humans to swim with dolphins.