Hola Nicole

Sorry about the delay.

We haven't got a lesson about this specific difference between the English and the Spanish. The reason why we cannot make it a lesson is because there is no specific pattern. This happens with some verbs, which in my opinion tend to be "verbs of perception", i.e. oir, escuchar, ver, oler... See these sentence and notice how in Spanish we don't need any modal verb, we simply use the verb directly:

1. No sé dónde está Laura. No la veo.

I don't know where Laura is. I cannot see her. 

2. Habla más alto, no te oigo. 

Speak louder, I can't hear you.

You can see that in the Spanish sentence we don't need to add "cannot". This is implicit.

Saludos

Inma