I am wondering whether the following forms are all okay:
- It was a 3-hour round trip to work.
- It was 3 hours' round trip to work.
- It was 3 hours round trip to work.
I'm sure #1 is correct. What about 2 and 3?
I'd appreciate your help.
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Sign up to join this communityI am wondering whether the following forms are all okay:
I'm sure #1 is correct. What about 2 and 3?
I'd appreciate your help.
You asked two things:
What part of speech is round trip? 2 Which sentence is correct?
It is being modified by what we call a compound adjective* ( **three-hour which describes how long the roundtrip journey will take).
The first sentence is correct because when you use a compound adjective the number part is always singular i.e. three not 3s. (see below about how to write numbers).
Other examples of compound adjectives are: -two- metre rope. -three- month break. -six- page document. -ten-minute walk. -ten- minute wait.
Notice the first word of each adjective is singular and that the adjective form is hyphenated although some texts don't hyphenate.
In you last two sentences you used plural forms of three which is wrong for this type of adjective. Also, you must write numbers from 0 to 100 as words according to the Chicago Manual of style.
I hope that helps in some way.
sources: Collins dictionary and Grammar for English language teachers by Martin Parrot