Modals

We use can to say that someone has the ability or opportunity to do something. The negative of can is cannot (contraction: can't). Can you swim? He can play the guitar. It's nice today. We can sit in the garden. I can't open this bottle. could for the italicized verbs if possible. 1. We had a good time yesterday. We went to the zoo. The children enjoyed themselves very much. They saw polar bears and elephants. (No substitution of 'could' is possible.) 2. When I lived in St. Louis, I went to the zoo whenever I wanted to, but now I live in a small town...