replace a phrase with ce qui versus en?

Question

when to use ce qui versus en to replace an entire phrase

Céline Pickard · Accepted Answer

Bonjour Connie,
In French, "ce qui" is used to replace something previously mentioned in the same sentence:
Julie a manqué son train ce qui est embêtant. = Julie missed her train which is annoying.
The pronoun"en" can also replace something previously mentioned (i.e. something introduced by"de" or an uncountable thing). However, it won't tend to be in the same sentence:
Louis parle tout le temps de ses problèmes ! - Oui, il en parle sans arrêt ! C'est agaçant ! = Louis is talking about his issues all the time! - Yes, he's talking about them non stop! It's annoying!
Hélène a besoin de patience ! - C'est vrai ! Elle en a beaucoup besoin. = Hélène needs a lot of patience! - That's true! She needs a lot of it.
Take a look at this lesson:
https://french.kwiziq.com/revision/grammar/the-adverbial-pronoun-en-can-replace-a-phrase-introduced-by-de
I hope this is helpful.
Bonne journée !