题目内容：

Today，an increasing number of people are always looking at their mobile phones with their heads down.These people are called the “Heads­down Tribe(低头族)”．Are you a heads­down tribe member？Heads­down tribe members now can be seen everywhere.

Using mobile phones may cause accidents and even cost a lot of money.Also，more and more interesting and strange facts happen to the “Heads­down Tribe”．Let's have a look at an interesting TV report.A man in America kept using his mobile phone on his way home.As a result，he bumped into a big lost bear on the street.When he lifted his eyes from the phone，he was so scared that he turned around and ran away as quickly as possible.Another fact is that we can often see people in the restaurant eating face to face but looking at their own mobile phones.It's strange that they don't talk to the ones who sit opposite to them during the meal.Some of them even have fun communicating with others on the phone.

Mobile phones are helpful and necessary tools for modern life.Are mobile phones good or bad？It depends on how people use them.Let's be “healthy” users and try to be the “Heads­up Tribe”．

1.Where did the American bump into the bear?

A. In the forest.    B. At a zoo.    C. On the street.    D. At a park.

2.According to the passage，what do the“Heads­down Tribe” do when they eat in a restaurant?

A. They enjoy their meals.    B. They take photos of their meals.

C. They don't talk to the people who sit opposite.    D. They talk to the strangers who sit next to them.

3.What do we know about the “Heads­down Tribe”？

A. They are cool children.    B. They are dangerous drivers.

C. They are good at using the Internet.    D. They are always looking at their mobile phones.

4.What is the main idea of the passage?

A. Let's try to be the “Heads­down Tribe”．    B. We should use mobile phones properly.

C. Mobile phones are not good for people.    D. Mobile phones are helpful and necessary.