黑板上用粉笔写着7个人名。There was a blackboard with seven names chalked on it.他在黑板上又写了几条注释。He wrote a few more notes on the board.他用一截粉笔将她的指示写在黑板上。With a stick of chalk he wrote her order on a blackboard....
Other electromagnets would push and pull the train along the track.其他的电磁铁会在轨道上拉或者推火车.The field may be provided by permanent magnets or by electromagnets.外地可能提供的永磁材料,或由电磁铁.Electromagnets would be used to dissipate the ene...