Look! This is a picture __________ my friend.[ ]
A. on
B. in
C. of
答案:C
It________heavily for 2 weeks and the farmers were very worried.
A.has been raining
B.had been raining
C.has rained
D.had been rained
如图所示,一质量为0.15千克、底面积为2×10-3米2平底薄壁玻璃容器放在2米2的水平桌面中央,内装有体积为1.5×10-4米3的水,水面距容器底的深度为0.1米。(g取10N/kg)
求:①水对杯底的压强;
②水对杯底的压力;
③若在容器中轻轻放下一块质量为0.1千克的木块,木块漂浮在水面上,求木块浸在水中的体积。
④求加入木块后(水未溢出)杯子对水平桌面的压强。