exercice anglais sur les modaux à corriger si nécessaire

[marcO]

Bonjour,
Pouvez-vous m'indiquer si mon exercice anglais sur les modaux est bon (can, could, may, must, will, would + qqfois négation )
"I saw John in Bath yesterday".
"You couldn't have seen him. He is in Paris. You must be mistaken".
"I don't think so. When did you last see him?"
"I saw him just before he left. He said that he will be back in June. Well, he also said that he would be back a little earlier to take his exams at university".
"You see. I can not get close and talk to him yesterday but he must be home by now and I'm sure he will call me soon".
"Can I ask you how you would be so sure he will call you ?"

[Kyoichi]

"You see. I can not get close and talk to him yesterday but he must be home by now and I'm sure he will call me soon".
"Can I ask you how you would be so sure he will call you ?"

alors, a mon avis,
au lieu de can la, je mettrai plutot couldn't a cause de "yesterday".
a la place du 2eme "can", je mettrais "May"... c'est +poli que "can" ^^
et enfin, a la place du would, je mettrai "can" par concordance de temps
voila voila.

[mwanasimba]

"I saw John in Bath yesterday".
"You can't have seen him. He is in Paris. You must be mistaken".
"I don't think so. When did you last see him?"
"I saw him just before he left. He said that he would be back in June. Well, he also said that he might be back a little earlier to take his exams at university".
"You see. I could not get close and talk to him yesterday but he must be home by now and I'm sure he will call me soon".
"May I ask you how you can be so sure he will call you ?"