A.10.2m/s B.1.02m/s C.12.0m/s D.1.20m/s
A.大于7.7s或小于14.3s B.小于7.7s或大于14.3s C.大于5.7s或小于16.3s D.小于5.7s或大于16.3s
A.6~12s B.7~13s C.8~14s D.9~15s