问题
选择题
荔枝种植是广东农业的“亮点”之一.某农民种植的荔枝因欠缺磷肥和氮肥而出现生长较慢,叶色泛黄,且产量低的现象.下列肥料最适合他用的是( )
A.尿素[CO(NH2)2]
B.磷酸二氢铵(NH4H2PO4)
C.磷酸二氢钙[CA(H2PO4)2]
D.氯化钾(KCl)
答案
NH4H2PO4含有氮元素和磷元素,所以最适合.故选B.
荔枝种植是广东农业的“亮点”之一.某农民种植的荔枝因欠缺磷肥和氮肥而出现生长较慢,叶色泛黄,且产量低的现象.下列肥料最适合他用的是( )
A.尿素[CO(NH2)2]
B.磷酸二氢铵(NH4H2PO4)
C.磷酸二氢钙[CA(H2PO4)2]
D.氯化钾(KCl)
NH4H2PO4含有氮元素和磷元素,所以最适合.故选B.
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The smell of old, dusty books reminds me of my father. An avid (贪婪的) 1 , he had many books, most of which went unread. He owned books on 2 from medicine to Vietnam to several sets of encyclopedias (百科全书). When I enter one of his 3 bookshops, such as Powell's, I am 4 back to a time when the two of us were 5 . I see him standing by a shelf, 6 through a medical magazine, or opening his wallet to pay for yet 7 book, knowing full well that Mom would 8 him on"wasting money on books you never 9 !" Walking past rows and rows of books in our study, I remember 10 , after the cancer struck, he came less and less and read fewer and fewer books. They became just part of the 11 , collecting only dust and 12 . Near the end, perhaps knowing he would never get to read them all, he gave almost all of the books away, 13 only a few. He treated them with an almost holy (神圣的) reverence (崇敬), 14 any crease (皱褶) or damage would destroy them totally. 15 was the man who would neglect a huge coffee mark, replaced by one who would get 16 suddenly at a small crease. I have read a few now, after he died, and each time it causes a 17 . But I suppose it is a kind of quest (追求), because if I can take on his thirst for 18 , cheerful smile, and willingness to help others, then like a match in the 19 , I will bring a little light into the world. And if that light touches others, maybe it will spread far and 20 , to light up the heavens. I think he'd like that. | ||||
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