题干

华北某地区经常出现苹果小叶病,有人认为是土壤中缺锌引起的,有人认为是土壤中缺镁引起的.现有如下材料,请你完成下列实验,探究上面的猜测哪个正确.

材料用具:三株长势相同的苹果幼苗、蒸馏水、含有植物必需元素的各种化合物.

实验原理:任何一种必需元素在植物体内都有一定的作用,一旦缺乏,就会表现出相应的症状,根据全素培养和相应缺锌、缺镁的培养对苹果生长发育的比较,判断小叶病的病因.

方法步骤:

(1)首先配制全素培养液和相应的缺锌培养液和 缺镁 培养液,分别放入三个培养缸并编号为A、B、C.

(2)____ .

(3)放在适宜的条件下培养一段时间,____ .

(4)结果预测和分析:

①____ 缸内的苹果幼苗正常生长.

②若B缸内苹果幼苗表现出小叶病,而C缸没有,则说明____ .

③若C缸内苹果幼苗表现出小叶病,而B缸没有,则说明苹果小叶病是由缺镁引起的.

④若____ ,则说明苹果小叶病既与缺镁有关,又与缺锌有关.

⑤若____ ,则说明苹果小叶病与缺镁、缺锌都无关.

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    The world always makes way for the dreamer

    When I was twelve years old, my father took me to see Zig Zigler. I remember sitting in that dark hall listening to Mr. Zigler1everyone's spirits up to the ceiling. I 2there feeling like l could do anything. When we got to the car, I turned to my father and said, "Dad, I want to3 people feel like that." My father asked me 4 I meant. "I want to be a motivational speaker just like Mr. Zigler." I replied. A(An)5  was born.

    Recently, I began seeking my dream of motivating others. 6  a four-year relationship with Fortune 100 Company 7as a sales-trainer and ending as a regional(地区的) sales manager, I left the company at the height of my8. Many people were9that I would leave after earning a six-figure income. And they wondered10I would risk everything for a dream.

    I made my 11 to start my own company and leave my worryingless position after12a regional sales meeting. The vice-president of our company made a13 that changed my life. He asked us, "If a god would offer you three wishes, what would they be?" After giving us a(an)14 to write down the three wishes, he then asked us, "Why do you need a 15 ?" I would never forget the power I felt at that moment. I realize that 16 I had accomplished in the past had prepared me for this moment. I was ready and didn't need a god's help to become a motivational speaker. A motivational speaker was17 .

    Having made that decision, I was immediately18 . One week after I gave notice, my husband was laid off from his job, and now we had no 19. But I held fast to my dream. The wonder really began to happen. In a short time my husband found a better job. And I was able to book several 20 engagements with new customers. I discovered the incredible power of dreams.