Hola Shirley

Depending on the context, ver and other perception verbs can be conjugated in the imperfect with the meaning of "could", without necessarily using the modal verb "podía...". So, the "could" is implied without having to use poder.

This is something that you can't normally do in English, but in Spanish you can. 

We have a lesson about this usage of the present tense with perception verbs instead of using the modal poder, but you can also apply this to the imperfect tense. Here is the lesson so you can see some examples. 

Saludos

Inma