2.248 numbers with time expressions

Cardinal numbers are sometimes used with general time words such as 'month' and 'week'. You do this when you want describe something by saying how long it lasts. If the thing is referred to with an uncount noun, you use the possessive form (see paragraphs 2.180 to 2.192) of the general time word.

Sometimes the apostrophe is omitted.

The determiner 'a' is usually used when you are talking about a single period of time, although 'one' can be used instead when you want to be more formal.

Cardinal numbers can also be used with general time words as modifiers of adjectives.