当knock off和knock over同时在表示“撞倒”意思的时候,knock over一般就是指撞倒（+ed被动）,比如说A boy was knocked over by a passing car but was fortunately unhurt.而knock off则指从某个地方（被）撞倒,如A boy was knocked off his bike by a passing car but was fortunately unhurt.你是不是的做区统练上的题?