逗号与枚举 -ag真人试玩平台

使用逗号分隔枚举中的项目。

example: old mcdonald had a pig, a dog, a cow, a horse.

“and”之前的逗号是可选的。

example:
 old mcdonald had a pig, a dog, a cow and a horse.
 old mcdonald had a pig, a dog, a cow, and a horse.

如果两个项目是同一个unit，请不要在“and”之前使用逗号 (“ham and eggs” as a dish is a unit and should not be separated by a comma.)

example:
 old mcdonald had soup, ham and eggs and apple pie for dinner.
 old mcdonald had soup, ham and eggs, and apple pie for dinner.

如果枚举中的所有项都以“and”, “or”, “nor”分隔，请不要使用逗号 

example:
 old mcdonald had a pig and a dog and a cow and a horse.
 old mcdonald had a pig or a dog or a cow or a horse.
 old mcdonald neither had a pig nor a dog nor a cow nor a horse.