'See' is a sense. We have five senses - see, hear, touch, smell and taste. We often do these things involuntarily. If your eyes are open you can see. If it isn't dark, you can see. To see is not an action - it is a sense and an ability. 'Watch' and 'look (at)' are actions. We do them voluntarily. We generally watch something that is moving (or likely to move), and we look at something that is static.

I would have to say that the difference in these words is more so in usage than in definition. The best way to learn the different uses is just by practice. Few examples: I watch TV. I am watching the game. I see you over there. I am seeing a new person (dating someone new). I saw the crime happen. I looked out the window. I am looking at a beautiful picture. I looked for my lost keys. I wish I could give a more specific explanation but I hope this helps a bit!

This is a good question, because these are all very important and common English words. Basically see = ver, look = mirar, watch = observar, but in practice it's not always so easy... Longman Dictionary gives a very good explanation here: http://www.ldoceonline.com/dictionary/see_1#p008-001929578 I agree also with Su.Ki.'s explanation, especially that we LOOK AT things which are still, and we WATCH things that move. I agree with Patrick that examples are helpful. He gave some good ones, but here are even more example sentences, including translations to Spanish: http://forum.wordreference.com/showthread.php?t=1485874&s=b1b727ce9f0c32f981df5b4fb8b8d08d&p=7510006#post7510006 http://forum.wordreference.com/showthread.php?t=840551&s=b1b727ce9f0c32f981df5b4fb8b8d08d&p=4513702#post4513702 It's worth noting that, with an object, look requires the preposition AT. You can't just "look something" Instead, you "look AT something". A lot of phrasal verbs are constructed with other prepositions to give different meanings -- like "look for" (= search for), "look up" (= check), and many others. Furthermore, as in Patrick's example ("I looked for (= searched for) my lost keys."; "I am seeing (= dating) someone new."), each of these words have additional meanings, besides their fundamental ones. It is well worth reading through the relevant dictionary entries: http://www.oxfordlearnersdictionaries.com/definition/english/see_1 http://www.oxfordlearnersdictionaries.com/definition/english/look_1 http://www.oxfordlearnersdictionaries.com/definition/english/watch_1 While these three are the most important, if you are interested in learning additional similar words, have a look here: http://forum.wordreference.com/showthread.php?t=179637&s=b1b727ce9f0c32f981df5b4fb8b8d08d&p=1129267#post1129267