题目

 Boys and girls, the books in the library should______ good care of. A. take B. are taking C. be taken 答案：C 解析:本句的真正主语是“the books”,应用被动语态，“should + be + 及物动词的过去分词”，故选C。4．已知2+$\frac{2}{3}$=22×$\frac{2}{3}$，3+$\frac{3}{8}$=32×$\frac{3}{8}$，4+$\frac{4}{15}$=42×$\frac{4}{15}$，…，若10+$\frac{a}{b}$=102×$\frac{a}{b}$（a，b为正整数），则2a+2b的值为218．