We live on the Earth. The green and brown parts are forests and land. The blue parts are oceans. The Earth1very clean and beautiful in the past, but now some parts of the Earth2dirty. Sometimes people throw rubbish3rivers and oceans.  Sometimes people cut down too many trees. Smoke from cars and factories makes the air dirty. The Earth gets sick. So people should stop cutting down so many trees. People should plant4trees. People should stop throwing rubbish. People should stop using plastic bags. People should work together 5keep the Earth clean and healthy.

— What is it? 

— .(它是地球)

— Are the blue parts oceans? 

— .(做肯定回答)