_B__is a good form of exercise for both young and old. A.The walk B.Walking C.To walk D.Walk
A.A
B.B
C.C
D.D
正确答案是B
_B__is a good form of exercise for both young and old. A.The walk B.Walking C.To walk D.Walk
A.A
B.B
C.C
D.D
正确答案是B