题目

  11. —Would you like to come to dinner tonight？     —I’d like to, ___ I’m too busy.     A. and . B. so     C. as. D. but 答案：D14．用简便方法计算下面各题．$\frac{2}{7}$+$\frac{1}{6}$+$\frac{5}{7}$=$\frac{4}{5}$+（$\frac{7}{8}$-$\frac{3}{4}$）             $\frac{7}{12}$+$\frac{3}{8}$-$\frac{1}{4}$+$\frac{5}{12}$．