The magnetic lines of force don't exist , they are defined by scientists.

磁力线并不存在，它是由科学家所定义。

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A changed particle moves along the lines of force of a magnetic field, spiraling as it goes.

带电粒子沿磁力线运动时就会发生回转。

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When a charged particle is in a magnetic field, it tends to travel along that field's lines of force, spiralling as it goes.

当一个带电微粒在磁场中时，它会倾向于沿着磁力线螺旋运动。

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In fact for readers of Paradise Lost, and this has been an experience now for a few hundred years, it does often seem as if there were some mysterious life force, a pulsating through Milton's dense and driving lines of unrhymed, iambic pentameter.

实际上，《失乐园》的读者们，几百年来一直都有这种体验，确实，似乎真有一种神秘的生命力，一种脉搏，贯穿在弥尔顿密集，强劲，没有韵律，长短不一的五音步格诗之中。

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In fact, the speech is perhaps the best example of the effective use of repeated lines that gather power and force with each repetition.

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In a 20-knot breeze the kite is already straining at the 500-pound test control lines with enough force to pull you halfway out of the water.

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