营养性缺铁性贫血的患儿最主要的特点是（）
A.小细胞低色素性贫血
B.大细胞低色素性贫血
C.正细胞正色素性贫血
D.大细胞正色素性贫血
E.小细胞正色素性贫血
参考答案：A
解析：贫血严重的时候，红细胞的体积减小，中央淡染区扩大(整个红细胞变小变浅)，称小细胞低色素性贫血。这种红细胞称低血色素红细胞。主要见于重度缺铁性贫血，是由于体内储存铁不足，妨碍了血红蛋白的合成。
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| As an exchange student, I have been staying in a host family in Beijing for the past five months. The parents are 1 in their mid-30s and the son just turned 5. In exchange for room and board, I teach their son 2 . Like in many of the other Chinese families, he's an only child. And though he has 3 plastic trucks and boxes full of crayons, I don't know 4 he has the time to play. When he's not in the kindergarten, he's taking after-school classes. On the weekends, the boy goes to more classes. He has one day off―Sunday. Compared to his schedule, I feel like my childhood was 5 a waste of time. I learned how to climb trees and draw cartoons. I wasn't learning Chinese at his age. But he and lots of other children are learning English. Both his parents dream that he will have 6 jobs, higher pay, and bigger houses. The boy seems to take no interest 7 learning English. He doesn't need a teacher, but a playmate. He is, 8 , only 5. When I think about my life as a 5-year-old, I know for sure I wasn't half as 9 as he is. In the evening, when his parents 10 him to speak with me in English, he gets 11 . He lies on the floors, hides under the table and climbs on the furniture. When he finally stops 12 , and starts talking, it isn't in English, but it isn't in Chinese, 13 . He speaks in his own language. He 14 not be a very good student, but I'm not a great teacher. I just want to be his big brother 15 can speak in gibberish (胡言乱语) with him and help draw trucks, robots or spiders. | ||||
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