题目

Peter:   What are you doing for vacation, Steven?Steven:  I’m visiting my aunt in San Francisco. My brother’s staying there. He’s joining a club.Peter:   Oh? When are you going?Steven:  Next Friday.Peter:   How long are you staying?Steven:  I’m staying at my aunt’s home for four days. I’m going sightseeing in San Francisco, and then I’m seeingall of my friends New York. How about you?Peter:   I’m going to the beach and my friends and I are also going hiking for a few days.Steven:  Aren’t you renting video tapes and relaxing at home?Peter:   No, it’s boring. We具有细胞壁的选项是( )A.花粉 B.红细胞 C.胰岛细胞 D.流感病毒