二、先通分，再比较大小。
$\frac{5}{7}$和$\frac{2}{3}$ $\frac{7}{12}$和$\frac{5}{8}$ $\frac{13}{12}$和$\frac{6}{5}$
$\frac{3}{5}$和$\frac{29}{50}$ $\frac{3}{40}$和$\frac{1}{6}$ $\frac{7}{8}$和$\frac{4}{5}$
$\frac{9}{32}$和$\frac{17}{48}$ $\frac{3}{14}$和$\frac{2}{7}$ $\frac{5}{12}$和$\frac{5}{9}$
$\frac{8}{15}$和$\frac{9}{20}$ $\frac{9}{32}$和$\frac{3}{4}$ $\frac{9}{25}$和$\frac{3}{10}$
$\frac{5}{18}$和$\frac{11}{24}$ $\frac{6}{13}$和$\frac{25}{52}$ $\frac{5}{16}$和$\frac{11}{32}$

$\frac{5}{7}=\frac{15}{21}$ $\frac{2}{3}=\frac{14}{21}$ $\frac{5}{7}＞\frac{2}{3}$
$\frac{7}{12}=\frac{14}{24}$ $\frac{5}{8}=\frac{15}{24}$ $\frac{7}{12}＜\frac{5}{8}$
$\frac{13}{12}=\frac{65}{60}$ $\frac{6}{5}=\frac{72}{60}$ $\frac{13}{12}＜\frac{6}{5}$
$\frac{3}{5}=\frac{30}{50}$ $\frac{29}{50}=\frac{29}{50}$ $\frac{3}{5}＞\frac{29}{50}$
$\frac{3}{40}=\frac{9}{120}$ $\frac{1}{6}=\frac{20}{120}$ $\frac{3}{40}＜\frac{1}{6}$
$\frac{7}{8}=\frac{35}{40}$ $\frac{4}{5}=\frac{32}{40}$ $\frac{7}{8}＞\frac{4}{5}$
$\frac{9}{32}=\frac{27}{96}$ $\frac{17}{48}=\frac{34}{96}$ $\frac{9}{32}＜\frac{17}{48}$
$\frac{3}{14}=\frac{3}{14}$ $\frac{2}{7}=\frac{4}{14}$ $\frac{3}{14}＜\frac{2}{7}$
$\frac{5}{12}=\frac{15}{36}$ $\frac{5}{9}=\frac{20}{36}$ $\frac{5}{12}＜\frac{5}{9}$
$\frac{8}{15}=\frac{32}{60}$ $\frac{9}{20}=\frac{27}{60}$ $\frac{8}{15}＞\frac{9}{20}$
$\frac{9}{32}=\frac{9}{32}$ $\frac{3}{4}=\frac{24}{32}$ $\frac{9}{32}＜\frac{3}{4}$
$\frac{9}{25}=\frac{18}{50}$ $\frac{3}{10}=\frac{15}{50}$ $\frac{9}{25}＞\frac{3}{10}$
$\frac{5}{18}=\frac{20}{72}$ $\frac{11}{24}=\frac{33}{72}$ $\frac{5}{18}＜\frac{11}{24}$
$\frac{6}{13}=\frac{24}{52}$ $\frac{25}{52}=\frac{25}{52}$ $\frac{6}{13}＜\frac{25}{52}$
$\frac{5}{16}=\frac{10}{32}$ $\frac{11}{32}=\frac{11}{32}$ $\frac{5}{16}＜\frac{11}{32}$