"Can"和"May"的区别
Can"和"may"都是用来请求许可的，但情况并非总是如此。在过去，“can”和“may”有明显的区别。“Can”用于表示能力(例如，Can you swim?)，“may”用于表示许可(例如，may I swim in your lake?)
由于有些人仍然遵守这种区别，下面的指导是适当的:
May for Permission. In a polite or formal setting, use "may" for permission. For example:
May用于许可。在礼貌或正式的场合中，使用“may”表示允许。例如
- May she swim in your pool?
(这个含义是"Is she permitted to swim in your pool?" 用may这么说比较礼貌.)
Can 用于许可. In an informal setting, it is safe to use "can" for permission. For example:
在非正式场合，使用“can”表示允许是不会错的。例如：
- Can she swim in your pool?
(含义与上面一致的，但听起来比较中性，与婉转的说法相比。)
Can用于能力. 例如:
- Can she swim?
(Is she able to swim?)
- Can she do quadratic equations? 她会解二次方程吗？
(Is she able to do quadratic equations?)
"may" 是不能用于表达能力。
关于"Can"的更多解释
"can" 是一个表达能力的助动词，例如:
- I can whistle.
(I have the ability to whistle.)
- Can he lift 150 kgs?
(Does he have the ability to lift 150 kgs?)
"Can" 也可以用于表达允许，例如:
- You can stroke the ponies but not goats.
(这里 "can" 表达许可. "Can" 在表达许可时，是在朋友之间或非正规场合。)
关于"May"的更多说明
"may" 是一个指代许可的助动词，例如：
- You can swim in this river.
(You are allowed to swim in this river.)
- May I have a biscuit?
(Am I permitted to have a biscuit?)
