在数轴上，表示与﹣2的点距离为5的数是（ ）．
3或﹣7
Kangkang is good _____ running. He thinks it is good _____ his health.[ ]
A. for; at
B. at; for
C. at; to
D. for; to
（）用于与EH的无线通信MHZ。
A.450MHZ
B.690MHZ
C.900MHZ
D.1000MHZ
