Si tu observas (watch) algo, significa que lo miras intencionalmente y con toda tu atención. Ejemplo: I watch television in the afternoon. Otro ejemplo: We watched the basketball match and cheered for our team.
Si tu ves (see) algo, significa que aparece ante tus ojos sin tu intensión. Ejemplo: I've never seen this TV show, but perhaps I should watch it sometime. Otro ejemplo: We saw a terrible accident on our way home and rushed to help the victims.
mirar
- to look, to look at, to face, to overlook, to watch, to consider, to think over
observar
- to observe, to watch, to notice, to obey, to abide by, to remark, to comment
ver
- to see, to see, to understand, to learn, to find out, to understand, to examine, to look into, to see, to judge, to meet with, to visit, to find out