日常生活中,我们给自行车打气时,发现越打越费力,是因为 [ ]
A.气筒摩擦越打越大
B.车胎内的气压越打越大
C.车胎内的温度越打越低
D.车胎内的体积越打越小
答案:B
— What's the noise? It sounds as if it comes from upstairs.
— _____. It must be the window-cleaner working, next door. [ ]
A. I'm not sure
B. I hope not
C. I'd rather not
D. I don't think so
简述《画品》中的六法。