题目

―Is ________ finished?―Not yet. My dirty clothes are still soaking in the washing machine.    A. something                B. anything                   C. nothing             D. everything 答案：D 一开口玻璃管竖直放置在小车上，小车沿倾角为37°的光滑斜面下滑．在运动前，玻璃管中有一段h=20cm的水银柱，封闭一段L0=40cm长的空气柱．设大气压强p0=75cm汞柱，温度不变，水银密度为=13.6×，g=10m/．（见图）求小车下滑过程中空气柱长为多少?