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1.一天,欢欢、乐乐等几个小伙伴去爬山。2.他们从山脚上山,上山的速度是2千米/时,到达山顶后沿原路下山,下山的速度是6千米/时。
1. One day, Huanhuan, Lele several other partners to climb. 2. They climb from the foot of the mountain, the speed of the mountain is 2 km / h, after reaching the top of the mountain down the road, down the speed of 6 km / h.