5.143 Duration expressions as modifiers

You can also use time expressions involving a cardinal number + a general time word to modify nouns. Note that an apostrophe is added to the time word.

• Four of those were sentenced to 15 days' detention.
• They want to take on staff with two years' experience.

This use of cardinal numbers is described in paragraph 2.248.

5.144

Time expressions are also used as compound adjectives to modify count nouns.

• They all have to start off with a six month course in German.
• I arrived at the University for a three month stint as a visiting lecturer.