题目

若组成蛋白质的氨基酸的平均相对分子质量是130，那么一个由4条肽链共280个氨基酸组成的蛋白质的平均相对分子质量是 A.31 432     B.31 486        C.31 378        D.36 382 答案：A 短文改错 正文中共有10外语言错误，请在错误的地方增加、删除或修改某个单词。增加：在缺词处加一个漏词符号(∧)，并在此符号下面写出该加的词。删除：把多余的词用斜线(＼)划掉。修改：在错的词下划一横线，并在该词下面写出修改后的词。 注意：1．每处错误及其修改均仅限一词； 2．只允许修改10处，多者(从第11处起)不记分． A ten-year-old boy entered into a coffee shop and sat at table．A waitress puts a glass of water in front of him．“How much is a chocolate ice cream?” “Fifty cents．” The little boy pushed his hand out of his pocket and counted the number of the coins．“How much are a dish of plain ice cream?” he asked．The waitress was a bit patient．“Thirty-five cents,” he said rudely．The little boy counted the coins again．“I’ll have the plain ice cream．” The boy finished the ice cream and paid for the cashier．When the waitress came back, she was surprising at what she saw．There were fifteen cents besides the empty dish, her tip．