سلام، آقاي Mohammad.mjsh!
همونطوريكه ميدونيد تركيب عدد-اسم در انگليسي ميتونه به عنوان "صفت" بكار بره، "پنج خوابه" اينجا صفته، پس نميتونه s بگيره،
(تا جايي كه من مي دونم، اگه بخواييم بعضي از صفتها رو به اسم جمع تبديل كنيم، از تركيب "the+ adj" استفاده مي كنيم
poor>>>the poor .)
براي مقايسه اين مثالها رو نگاه كنيد:
Number+ noun:as a noun modifier (adjective)
In these cases: the noun is singular and a hyphen is used.
The ladder has five steps.>>>>> it is a five-step ladder.
The program has one step. >>>>>>> it is a one-step program.
The book has two hundred pages.>>>>> it is a two-hundred-page book.
Bruce's workout lasted 10 minutes. >>>>>it was a ten-minute workout.
Bruce worke 10 days.>>>>> it was a ten-day job.