小球沿一曲面滚动，间隔相等时间所拍摄的照片如图所示，可知小球的运动速度是先变 ____ ，后变 ___ ．
大；小
Woman: I paid 50 dollars for these books at the Eaglewood Bookstore. They're really too expensive. Man: Too expensive They cost a lot more in other bookstores. Question: What does the man mean
A．He thought they were expensive.
B．He didn't think they were expensive.
C．He wanted the woman to buy books in other bookstores.
D．He thought books in other stores were just as expensive.
冶金焦和气煤焦有什么不同？
