① Let's go home! ____     A. It's 9 o'clock．

② Where is Amy? ____     B. Yes．I do．

③ What time is it now? ____     C. OK．

④ Do you like music class? ____     D. She is in the art room．

$\frac{3}{5}$ ____ $\frac{13}{15}$           $\frac{5}{12}$ ____ $\frac{7}{20}$          $\frac{5}{6}$ ____ $\frac{4}{9}$

$\frac{3}{8}$ ____ $\frac{9}{24}$          $1\frac{1}{12}$ ____ $\frac{5}{4}$          $\frac{5}{18}$ ____ $\frac{7}{12}$

某型号的电饭锅有两档，其原理如图所示，电阻R₁=44Ω，当开关S闭合时，电饭锅处于高温档，当开关S断开时，电饭锅处于焖饭、保温档，焖饭、保温时电饭锅的功率为高温档功率的0.02倍，求：