A、B两点的坐标分别为(1,0)、(0,2),若将线段AB平移至A1B1,点A1、B1的坐标分别为(2,a),(b,3),则a+b=____.
—Is your sleeping problem getting better? —No. And . They gave me the wrong medicine this time. Can you believe that?
对于平抛运动,下列说法正确的是( )
水稻生活中,需要量最多的无机盐是( )
—I have difficulty in learning Chinese. Could you give me some help?
—Sure. Reading a lot will help you improve your Chinese.