植物的生长需要多种无机盐，其中需要量最多的三种无机盐是（ ）
A．氮、镁、钾
B．氮、磷、钙
C．氮、磷、镁
D．氮、磷、钾
答案：D
题目分析：无机盐对植物的生长发育起着重要的作用，这些无机盐包括含氮、磷、钾、钙、镁、硫、硼、锰、锌、钼等的多种无机盐，其中植物生活中最多的无机盐是含氮、磷、钾的无机盐．含氮的无机盐能促进细胞的分裂和生长，使枝繁叶茂；含磷的无机盐可以促进幼苗的发育和花的开放，使果实、种子提早成熟；含钾的无机盐使植物茎秆健壮，促进淀粉的形成与运输．故选：D
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| The first day of school our teacher let us know someone. Looking out, we found an old woman 1 at the door. She said,"Hi, my name is Susan. I am seventy years old". While we were 2 what made her take this 3 at her age. She said with a smile."I'm here to meet a rich husband, get 4 , have two children and travel together." Hearing this, all of us laughed."In fact,"she went on," I always 5 of having a college education, and now I'm getting 6 !" After class we had chocolate and milk together. We became good 7 . I often listened to this "time machine" as she shared (分享) her 8 with me. At the end of the term we invited Susan to give us a 9 . When she was stepping up to the podium (讲台), suddenly she found she took the wrong paper. She felt a little 10 and said, "I am sorry. I am so nervous. I can't get my ready talk 11 , so I have to tell you 12 I know." In her speech she told us" We don't stop playing as we are old, we grow old 13 we stop playing. The secret of staying 14 , being happy and getting success is that we should laugh and find something 15 every day. I think there is a great 16 between growing old and growing up. I am seventy now. If I 17 in bed for one full year and never do anything, I'll become seventy-one. Since anybody can grow older, my 18 is to grow, up by always finding the chance in change. Growing older can't be avoided (避免), growing up can be 19 . It's never too late to be all you can possibly be." During the four years' study, it was so easy for Susan to make friends 20 she went. In the end, the wonderful woman got the college degree (学位). | ||||
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