‘Qui’ and ‘que’ are both relative pronouns.
At first it can be hard to know which one to use in a sentence. However, it is simply a case of learning the rules. You will be able to use them in no time!
‘Qui’ is a relative pronoun. It replaces the subject (person, object) in the subordinate clause.
Le garçon, qui est amoureux de Juliette, va au cinéma ce soir.
The boy, who loves Juliette, is going to the cinema tonight.
Remember: a subject is the person doing the action.
The subordinate clause provides the reader with extra information about the boy: he loves Juliette.
If the relative pronoun ‘qui’ in the subordinate clause ‘qui est amoureux de Juliette’ is substituted with the boy’s name, it reads, 'Le garçon est amoureux de Juliette', which makes perfect sense.
'Qui' can also be translated by 'which'.
'Que' is also a relative pronoun. It replaces the direct object (person, object) in the subordinate clause.
L’électricien que j’ai rencontré la semaine dernière est malade.
The electrician whom I met last week is ill.
So, how can we check that ‘L’électricien’ is the direct object of the sentence?
By splitting up the clauses.
J’ai rencontré l’électricien la semaine dernière. Il est malade.
‘J’ai’ is the subject of the sentence, while ‘l’électricien’ is the direct object.
When broken up into two separate sentences, ‘l’électricien’ becomes the subject of the second clause. ‘Est malade’ - ‘Is sick’ would not make sense by itself.
'Que' can also be translated by 'that'.