题干

目前,全世界都在积极防治甲型H1N1流感。甲型H1N1流感病毒是一种RNA病毒,我国已研发出甲型H1N1流感疫苗并对有关人员进行了免疫接种,使许多人获得对该病的抵抗力。下列有关叙述中,正确的是

A:接种甲型H1N1流感疫苗属于人工被动免疫

B:感染了甲型H1N1流感病毒后,人体只需细胞免疫发挥作用

C:可用经灭菌的动物细胞培养液培养甲型H1N1流感病毒,使之大量增殖

D:甲型H1N1流感病毒没有核糖体,组成其遗传物质的核苷酸只有4种

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D

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    Seven years ago, I began accompanying my father to the local market to sell vegetables we harvested from our farm. At the beginning , I did what I could to1him while I also communicated with other participants in the market.

    As time went by, I increasingly2the craft of gardening,3I began planting a garden of my own to4a seller myself. The market soon became my5for many summers to come. The sellers in the market were6and more than willing to share their gardening experience. Many sellers were the new generation of farmers and acquired knowledge through the experience of their7. The years I participated in the market helped me grow, taught me many new skills and opened doors to success I8imagined.

    Responsibility came rather quickly as I 9to manage my own gardening business. There was a huge of work being self10. I had to do everything by myself. I learned that self-discipline(自我约束) and time management were important in order to11a productive garden. Rising 12in the morning at 4 a. m. to arrive at the market with my13produce ensured I would be there to greet early 14 .

    The market opened a door of opportunity I never dreamed of. It15me to make a profit to start a greenhouse business. It is a(n)16feeling when I see the seeds come out and raise them as they continue to17until they are ready for sale. I've learned18because it is impossible to rush Mother Nature! It takes time and work to make the plants grow and become mature. It is not an overnight19. Several weeks are required for the plants to be ready, but the 20is worth all the time I spend and all work I do.