Nowadays there are still a number of students school at various grades due to a lack of mo

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A. leaving out
B. making out
C. letting out
(答案→)D. dropping out
解析：考查动词短语辨析。句意为“当今，在中学与小学各阶段里，仍有许多贫困地区的孩子因没钱而辍学。”drop out “退出，辍学，离队”，符合句意。leave out“省去，略去”；make out“理解，了解，辨认出”；let out“放掉，泄露，放大”，均不合句意。