From a list of sentences banned last year by the Chaoyang District Education Committee in Beijing (in other words, Chinese teachers can no longer say any of the following):

-You are slow and stupid.
-Have your mother take you for a check up--to test if you are retarded.
-You are hopeless and incurable; no medicine can save you.
-I believe you will have no future.
-Retard.
-You are only a wood post with two ears.
-Stupid, you just can't learn anything.
-How can you be so lazy like a pig?
-You only fill your stomach and daydream; you can do nothing but eat and you are hopeless.
-The sight of you makes me sick.
-Sit down stupid; don't raise your hand unless you know the right answer.
-I would have killed myself long ago if I were you.

Source:Harper's Marazine (Aug. 2002)