Răspuns:
While Alex and Sue were watching a film on DVD, their friends arrived.
Alex and Sue were watching a film on DVD when their friends arrived.
While Marco was having breakfast, he had a great idea.
Marco was having breakfast when he had a great idea.
While Cristina was talking o the phone, her father went out.
Cristina was talking on the phone when her father went out.
While they were walking in the mountains, they saw a strange a bird.
They were walking in the mountains when they saw a strange bird.
