将一张0.12mm厚的白纸对折20次后，列式子表示厚度是______mm．
∵对折n次的厚度为0.12×2nmm，∴对折20次的厚度为0.12×220mm．
－What do you think of the talent show in our school?
－ I think teachers in Grade Two were ___________ act _____ all.
A．the funniest ; in
B．the best; of
C．the goodest; in
D．the most good; of
甲亢术后呼吸困难多发生于术后（）。
A．6小时以内
B．12小时以内
C．24小时以内
D．48小时以内
E．72小时以内
