posted by John .
1. I applied cosmetics on my face.
2. I applied the cosmetics on my face.
3. I applied makeup on my face.
4. I applied the make-up on my face.
Which expressions are correct?
All seem to be correct, except that I don't think the hyphen is needed in #4.
Thank you. By the way. in which case do we use 'the'?
Most of the time "the" is used to indicate something rather specific. It's idiomatic, though, and not always easy to explain or understand.
Here's a webpage where articles (a, an, the) are discussed: