①是生物膜的重要成分②是储能的分子③生物体内脏器官的保护层④是很好的绝缘体，具有保温作用⑤具有生物学活性，对生命活动起调节作用

    Charles Dickens (1812—1870), the great nineteenth century English novelist, was born near Portsmouth. His father ran heavily into debt (债) and when he was twelve, he had to go and work in a factory. The only formal education he received was a two-year schooling at a school for poor children. In fact, he had to teach himself all he knew. He worked for a time in a lawyer's office. After that, he worked as a reporter in the law courts, and later for London newspapers. His life as a writer of novels began in 1833 with short stories and essays in newspapers, and in 1837 his novel “The Pickwick Papers” made him the most popular author at his time in England.

    He was a great observer (观察者) of people and their places because he was concerned about life and conditions in mid-nineteenth century London. He wrote 19 novels all his life and in many of them, Dickens gave a picture of all classes of England society, showing deep concern for the poor.

    Many of his novels like “Oliver Twist”, “David Copperfield”, “Nicholas Nickleby”, “Great Expectations”, “A Tale of Two Cities” and so on drew attention to the unfair social conditions that existed in England over a hundred years ago. Dickens wished to see improvement in the living conditions of the poor, but failed to find any useful method to achieve that goal.