Réponse:

en fait which s'utilise pour dire "who" mais lorsque le sujet est un objet inanimé et après c'est de la logique et dépend des phrases

b. the harbour Bridge which joins...

c.the Sydney eye which is the tallest....

d. the Olympic stadium which was...

Réponse :

a. The Opera House which was designed by a Danish architect is the symbol of Sydney.

b. The Harbour Bridge which is made of steel joins the two headlands of Sydney.

c. The Sydney Eye which i visited last year is the tallest building in Sydney.

d. The Olympic stadium which was the centre of the 2000 Olympics is being redeveloped.