题目内容：

Brush your teeth every day， dentists say. In the south of Africa， some people brush their teeth all day long.

They keep a small stick in their mouth to chew or scrub (洗刷） their teeth all day. People cut the sticks from trees. They are the African toothbrushes. People there are used to brushing their teeth with sticks.

Africans think the sticks work better than toothbrushes. The sticks come from nature， and it is said that there is something special about them. The special thing may stop many kinds of tooth problems. “If you have a bad tooth， it is a medicine，” said Diop， a seller in Africa.

The sticks are also much cheaper than toothbrushes.

In Senegal (塞内加尔），the chewing stick is called “sothio”. It means “to clean” in their language. In east Africa，the stick is called “mswaki”. It’s their word for “toothbrush”.

Even the dentists agree that the sticks seem to clean teeth better. Nowadays， some nice health stores in the United States start to sell chewing sticks. They think that the stick is natural kind of tooth care.

1.Who brushes teeth with sticks first according to the passage?

A. The Africans.            B.The Americans.

C. The Chinese.           D.The dentists.

2.When do the people in the south of Africa brush teeth with sticks?

A. In the morning.   B. In the afternoon.

C. In the evening.   D. All day.

3.Which of the following is NOT true according to the passage?

A. The sticks with something special in it may stop many tooth problems.

B. The sticks， which come from nature， are much cheaper than toothbrushes.

C. The chewing stick， which is called “sothio”， means “to clean”in east Africa.

D. People can buy chewing sticks in the nice health stores in the US.