P.8 In the United States there are two kinds of television stations. One kind is commercial. About 841 of the television stations in the United States are commercial stations. These stations are businesses. They show ads to make money. The other kind of television station is public. These stations do not show any ads. They get some money from the government. They also get money from the people who watch public stations.
a. the two kinds of television stations in the U.S.
b. public television stations.
c. television in the United States.
P.9 Some of the largest trees in the world are in California. These are called redwood trees. Redwood National Park is a large forest of redwood trees. Some redwoods are hundreds of years old. These old trees are very tall. They are also very wide at the bottom. One tree has a large hold in the bottom. The hold is so big you can drive a car through it.
a. parks in California.
b. redwood trees in California.
c. the age of redwood.
P.10 Large forests are important to us in many ways. They give us wood for building and heating. They are a home for many kinds of plants and animals. And for many city people, forests are a place to go for a vacation. People can learn about nature there. They can breathe fresh air and sleep in a quiet place. But there is one more reason why forests are important for everyone. The leaves on the trees in a forest help clean the air. Dirty air is a problem in many parts of the world. Without our forests this problem might be much worse.
a. the importance of forests.
b. taking vacations in forests.
c. large forests.