— That's true. A happy family provides a loving ________ for its children.

A: Hey, Jeff!

B: It's hard to say. What's your prediction about that?

A.

B: Oh, no. Then cities will be more and more crowded.

A: In 80 years, some of us will live on another planet.

B: Mars (火星) or Venus (金星)?

A: Mars. I heard scientists found water on Mars.

B: Wow, that's great.

A: You're right.

— Everyone should play a part in ________ the earth.

    Every year thousands of young people in England finish school and then take a year off before they start working or going to university. Some young people go to other countries and work as volunteers.

    Volunteers give their time to help people. For example, they work in schools or hospitals, or they do something helpful for the environment.

    Paul, 18, comes from Wales. Next year he wants to get to university to study Chinese, but now he's living in Belize. Paul says, "I'm working with other people here to save the coral reefs (珊瑚礁) in the sea near Belize. The reefs here are beautiful, but if the sea water is polluted badly, the coral will die. I'm helping to do study on the coral and the fish that live around the reefs. All over the world, coral reefs are dying. We need to do something about the problem before it's too late. I'm staying with a family here. I help do some housework. I don't get any money, but that's OK. I love my work here, and I'm learning a lot about the people of Belize! When I finish my work, I want to stay here for another three months. I want to travel around Belize and Central America.