If the blocks are placed off-centre, they will fall down.积木如果搭得中心错位就会倒塌。Babies often fall down when they learn to walk.婴儿在学走路时经常摔倒.Babies often fall down when they are learning to walk.小儿学步时常会跌交....
全国的铁路系统几乎全部实现了电气化.The national railway system has nearly all been electrified.你一定疯了,竟穿越那条电气化列车轨道.You must have been round the twist to walk across the electric railway tracks.是的.农村 电气化 也是了不起的事.Electrification of the coun...