题干

对流行性腮腺炎的研究发现:病原体能够通过细菌过滤器,用RNA水解酶处理后失去感染性;该病主要通过飞沫传播,危害性很大;接种疫苗是预防该病最行之有效的方法。下列说法正确的是(  )

A:该病原体含有的元素中一定有N和P

B:该病原体的细胞壁不能被纤维素酶水解

C:接种疫苗后产生的干扰素可使病原体凝集

D:该病原体遗传物质的基本单位是脱氧核苷酸

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A

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    In 1971 a young man who grew up very poor was traveling across the country, trying to make a new start for himself. Along the way he had completely run out of(用光了...) money and was forced to spend the night in his car. This continued until one morning, after a week of sleeping in his car, he walked nervously into a restaurant and ordered a big breakfast.

    After eating his first good meal in weeks, he found himself lying to the waiter, telling him he had lost his wallet. The waiter, who was also the owner, walked behind the chair where the young man had been sitting. He bent down, and came up with a $20 bill that looked as if it had fallen on the floor and said, “Son, you must have dropped this,”the owner said. The young man couldn't believe his luck! He quickly paid for the breakfast, left a tip, bought gas with the change, and headed West.

    On the way out of town, he began to understand what the owner did. Maybe nobody dropped the money at all.“Maybe that fellow just knew I was in trouble and he helped me in a way that didn't embarrass(使尴尬)me. So I just made a promise to help other people if I can.”

    Later, he worked very hard and became a rich man. Now he lives near Kansas City. Each year he gives away thousands of dollars. He is known as the “Secret Santa” because at Christmas time each year, he personally hands money out to those on the street and at restaurants. Last year, he gave more than $50,000 away in Kansas City.