The little girl was ________losing her life,but she is now ________. A. in the danger of ;out of danger B. in danger of;out of the danger C. in the danger of;out of the danger D. in danger of;out of danger 答案:D一台起重机的钢索最大拉力为5×104 N,起重最大时速18 km/h,用它来吊起一个4 t的货物,为了安全,使货物达到最大速度的时间至少为多少秒?