各种蛋白质的含氮量平均约为() A.8% B.12% C.16% D.20% E.2 发布时间:2017-05-23 15:38 │ 来源:www.tikuol.com 题型:单项选择题 问题: 各种蛋白质的含氮量平均约为()A.8%B.12%C.16%D.20%E.24%
题型:单项选择题 Of the making of good books there is no end; neither ________ any end to their influence on man's lives.[ ]A. there is B. there areC. is there D. are there 查看答案