题目

朋友跟你说他有一支蜡笔，你想表达你也有，应该说： A . I have a crayon. B . Me too. 答案：B15．能简算的要简算．$\frac{7}{12}-\frac{5}{24}+\frac{2}{3}$$\frac{1}{2}-\frac{1}{3}-\frac{1}{6}$$\frac{4}{7}+\frac{5}{11}+\frac{5}{7}$1-$\frac{1}{4}-\frac{3}{4}$$\frac{5}{8}+\frac{2}{11}+\frac{9}{11}$$\frac{11}{12}+\frac{1}{6}-\frac{5}{24}$$\frac{5}{7}+\frac{5}{9}+\frac{2}{7}+\frac{4}{9}$$\frac{5}{6}-\frac{5}{7}+\frac{1}{6}-\frac{1}{7}$$\frac{4}{5}-（\frac{1}{4}+\frac{2}{5}）$．