Réponse :
3.
a. Science has became incredibly frightening
b. have hit
c. He hasn't forgotten
d. He has catch
e. They have hiden
f. Jenny hasn't spoken
4.
a. She was over the moon when she has made that discovery
b. You have come to the conclusion that this vaccine wouldn't work
c. He realized he had been too optimistic
d. They developed some revolutionary drugs
e. We have started panicking when we thought of the consequences
f. They have never felt so fit
