The twins __________ in Dalian last year. They ___________ here now. ( )
A:are; were
B:were; are
C:was; are
一次函数y=kx+b(k,b为常数,且k≠0)的图象如图所示,根据图象信息可求得关于x的方程kx+b=0的解为( )
下列不属于性状的是( )
The water is not _______ enough. Add some more sugar, please.
如图所示,固定的光滑轨道MON的ON段水平,且与MO段平滑连接.将质量为m,的小球a从M处由静止释放后沿MON运动,在N处与质量也为m的小球b发生正碰并粘在一起.已知MN两处的高度差为h,碰撞前小球b用长为k的轻绳悬挂于N处附近.两球均可视为质点,且碰撞时间极短.