Bonjour !
On compte 9 auxiliaires modaux en anglais : Can, could, must, may, might, shall, will, would et should
I was with him in the kitchen when the jewel was stolen in the bedroom so he could be (pourrait être) the thief. I can (je peux) recognise the suspect, but I really didn't see him very well. We found this knife covered in blood at the crime scene. It must be (obligation) the murder weapon. The light was off, but I think I recognised the way he walks. He would be (serait) the culprit.
