A.x>2B.x<3C.x≠3或x≠2D.x≠3且x≠2
答案:D
--There so many foreigners in the streets these days.
-- They might be runners in the Yellow River Estuary (入海口,河口) International Marathon.
A.is
B.are
C.have
D.will be
水面很宽的一条河,越靠近河中心水的流速越大,小船渡河时船头垂直河岸且垂直河岸的速度不变,则小船( )
A.渡河的轨迹为曲线
B.渡河的轨迹为直线
C.到河中心时速度最小
D.到河对岸时速度最大