■ may not

一般语法书认为，may not 的意思是“得到允许可以不做某事”或者“也许不会做某事”。

• She may not come to the party. (= perhaps she will not come.)她也许不会来参加联欢了。
• I might not go to work tomorrow. (= perhaps I will not go.)我也许明天不去上班了。
• The use of aspirin and other anti-inflammatory drugs may not reduce the risk of colorectal cancer.服用阿斯匹灵和其他消炎药可能并不降低患结肠直肠癌的风险。

但是，在实际语言中，may not 也可以表示禁止。

• Bikes may not be stored on or next to the balcony.自行车不可以储藏在阳台上或阳台旁边。
• Cars may not exceed 10 mph on the school ground.汽车在校园内车速不得超过每小时十英里。
• You may not bring these things to school.你们不可以把这些东西拿到学校里来。
• You may not copy, reproduce, upload, post, distribute, republish, retransmit, or modify in any way any of the material on this site.您不可以以任何方式抄录、复制、上载、张贴、散发、再发表、转递或是修改本网站上的任何材料。