Is there a rule of thumb on when to use de, sur, à propos de, and, au sujet de, when translating them as "about"?
De can mean "about" like in:
J'ai parlé de...
(I spoke about)
Sur can mean "about" in:
Un livre sur...
(A book about)
À propos de:
Nous parlons à propos de...
(We're talking about)
And
Un livre au sujet de...
(A book about)
I'm not sure when to use which, and I'm not even sure if all my sentences are correct.
