Réponse :
Question 3 :
Dorian seems to feel nostalgic and sad by thinking of his portrait Hallward his goodlooking face. We can Imagine that Dorian became old and lost is handsomeness by aging or maybe Dorian has now scars on his faces that make him look ugly.
Question 4 :
The reason why Dorian is feeling sad are the following : he grew up "horrible" and "dreadfull" (précise la ligne sur ta copie). Dorian lost his beauty while aging.
Explications :
