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Former Presidents (前任总统) in the United States continue to receive special government services and money after their presidential term (总统 任期) ends. Each former president receives retirement pay, money to pay travelling expenses and money to pay the people who continue to work for them. They also get security 1 for the rest of their lives.
Some former presidents seem to have 2from public life. But others continue to make contributions (做贡献) to the society.
Former President Jimmy Carter is well known for his earnest devotion (热诚的奉献) since he left office. He helps build homes for poor Americans and helps settle international disagreement. And he has written several books. Many people have called Carter an example of a successful former president. Some experts note that public approval (公众的赞许) of Carter increased several years after his defeat in the presidential election (总统大选) of 1980.
3 the opposite happened to former president Ronald Reagan. His popularity fell after he left office. Many people criticized him for4 an offer from a wealthy Japanese publisher to visit Japan. There he was paid about two million dollars just to make a few appearances. In 1994, Reagan began to suffering from Alzheimer's disease (老年痴呆症) and died ten years later.
Former President George Bush has made few 5 appearances since leaving office. Recently, however, he and former President Bill Clinton have traveled together to places in need of aid following natural disasters.
Bill Clinton is one of the most active former presidents. He makes speeches around the world. He wrote a best-selling book about his life. And he has set up a foundation that offers various 6 to people in need, including providing low cost medicines for people with AIDS around the world.
常常碰到涉及化学知识的某些问题，下列叙述正确的是