knock off和knock over的区别

简单的讲，knock off 更强调从原有的位置消失；而knock over 更强调姿态上的歪斜。除了撞倒，其实还有很多其他更常用的含义。

knock over:

1
a (1) : to strike to the ground : fell (2) : overwhelm b : eliminate
2
a : steal; especially : hijack b : rob

knock off:
v.tr.
1. To strike with a hard blow: knocked him on the head.
2. To affect in a specified way by striking hard: knocked the mugger senseless.
3. To cause to be displaced or unengaged; force: a wind that knocked the tower over; a blunder that knocked him out of the job.
4. To cause to collide: I knocked my head on a low beam.
5. To produce by hitting or striking: knocked a hole in the wall.
6. Informal To find fault with; criticize: Don't knock the food; it's free.
v.intr.
1. To strike a sharp audible blow or series of blows, as on a door.
2. To collide with something: knocked into the table.
3. To make a pounding or clanking noise: The car engine is knocking.
n.
1. An instance of striking or colliding.
2. The sound of a sharp blow on a hard surface.
3. A pounding or clanking noise made by an engine, often as a result of faulty fuel combustion. Also called ping.
4. Slang A cutting, often petty criticism.