"He is not wearing the clothes."
Translation:Han har ikke tøjet på.
why "tøjet" and not "tøjerne"? Just a guess: if the subject was plural "de" then I would use "tøjerne"?
tøj is both singular and plural. Think of it as english clothes. And you have to use tøjet because it's a definite noun (the clothes)
Because no one uses the word "klæder". It is very formal/antique. The only use of it that I can think of is in the title of the fairy tale "Kejserens nye klæder".