當(dāng)knock off和knock over同時在表示“撞倒”意思的時候,knock over一般就是指撞倒（+ed被動）,比如說A boy was knocked over by a passing car but was fortunately unhurt.而knock off則指從某個地方（被）撞倒,如A boy was knocked off his bike by a passing car but was fortunately unhurt.knock off:
knock off
打翻;撞倒
撞倒;打掉
The little girl knocked the glass off by accident.小女孩不小心碰落了玻璃杯.
減去
They knocked off five dollars from the price.他們把價格降低了五美元.
停止;歇工
Let's knock off now.咱們現(xiàn)在歇一會兒吧.
knock over
打翻;撞倒
He knocked a glass over.他把玻璃杯打翻了.
使驚奇
She was knocked over by the news.她被那消息驚呆了.
消除
We have knocked over every difficulty.我們已排除種種困
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