A.5Hz,10A
B.50Hz,10A
C.50Hz,10 A
D.5Hz,10 A
答案:B
下列图象中,可以表示物体做匀加速直线运动的是( )
A.
B.
C.
D.
She always watches her son ________ the road every morning, or she will feel worried.
A.crossing
B.cross
C.to cross
D.to crossing