【问】(A) He may not he there. (B) He can't be there. 这两句话的意思相同吗? 【答】 这两句话的意思是完全不同的。在can not结构中,否定词not是否定助动词can的:Hecan't be there.=It is not possible that he is there.他不可能在那里。类例: 1. You can't be serious. =You must be joking. 你不可能是当真的。=你一定是开玩笑。 2. He can't be more than thirty. (Wells) 他不可能超过三十岁。 3. If he said that,he can't be telling the truth.(Eckersley) 如果他说过这话,那他不可能说的是真话。 4. She can't be awake. 她不可能是醒着的。 而在may not结构中,当may作“可能”解时,否定词not一般是否定其后的成份的。Hemay not be there. =It is possible that he is not there.(他可能不在那里。)类例: 1. You may not be serious. 你可能不是当真的。 2. That may not be true. 那可能不是真的。 但是,当may (might)作“允许”解时,则not常常是否定may (might)的: You may not go swimming today.(CGEL) 今天不许你们去游泳。 请做下面的英语试题: The sign on the lawn says clearly that people____on the grass. A. will not walk B. might not walk C. have not walked D. may not walk (参见may not/might not)