调频波的频率分量有无穷多个。
参考答案:对
如果点P(m+3,m+1)在直角坐标系的x轴上,P点坐标为( )
A.(0,2)
B.(2,0)
C.(4,0)
D.(0,-4)
I have devoted four weekends to writing papers and now I feel I ________ a rest.[ ]
A.deserve
B.preserve
C.perceive
D.receive