题目

Regular safety checks and maintenance of escalators(手扶电梯) and elevators have been urged in the wake of a tragedy in Central China’s Hubei province. A woman fell   76 a gap at the top of an escalator at a department store.   77 woman aged 30 managed to push her two-year-old boy to   78(safe) at the top of the escalator. Video at the shopping mall shows the woman   79(hold) her son as she prepares to get off the escalator when a footplate collapses under her feet.   80(stick) in the hole and with only her upper body above the structure, she pushed her son forwards 用竖式计算．42×19= 354÷6= 64×35= 5.4+1.36=