在平面直角坐标系中,点(3,-4)所在的象限是( )
A.第一象限
B.第二象限
C.第三象限
D.第四象限
∵点的横坐标3>0,纵坐标-4<0,
∴点P(3,-4)在第四象限.
故选D.
18. ______ by Liu Qian’s show, many students have fallen in love with the art.
A.Attracting
B.Attracted
C.Being attracted
D.To attract
一种标示重量为10g的黑膏药,其重量差异限度为()
A.±5%
B.±6%
C.±7%
D.±8%
E.±9%