用所给词的适当形式填空
(1)He came back home early____(cook)supper for his son.
(2)What about____(play)football after class?
(3)Do you like____(Europe)modern music?
(4)The Smiths____(be)here in two minutes.
(5)We all know a Chinese soldier____(call)Lei Feng.
下图是明代宋应星所著《天工开物》中的“斩竹漂塘”、“荡料入帘”插图,图中所示的这项古代中国重要发明
汽车在平直公路上行驶,在它的速度从零增加到v的过程中,汽车发动机做的功为W1;在它的速度从v增加到2v的过程中,汽车发动机做的功为W2.设汽车在行驶中发动机的牵引力和所受的阻力都不变,则有( )