线圈形成的磁场抵消掉磁铁的磁场之后，既可是触点打开。
The field from the coil opposes the field of the magnet, allowing the contacts to open.
磁铁的磁场跟电流的磁场一样，都是由电荷的运动产生的。
The magnetic field of magnet is the same with the magnetic field of electric current, they all caused by the movement of electric charges.
他把几块磁铁合并起来加强了磁力，儿子说他知道这正显示了磁铁的磁场。
He was using several magnets together which compounded the effect. He said that he knew it was a demonstration of the magnetic field of the magnets.
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