点(2,3,4)关于x轴的对称点的坐标为_____
(2,-3,-4)
题目分析:空间直角坐标系中点关于轴对称,则纵坐标与竖坐标不变,横坐标变为相反数.
— ______ he ______ at this school last term?
— Yes, I think so. [ ]
A. Did…study
B. Does…study
C. Was…study
D. Did…studied
一只小鸭浮在平静的湖面上.下图能正确表示小鸭和它在水中所成的倒影的是( )
A.
B.
C.
D.