Student or Learner
Does "saw" mean "actually witness or watch" or "realize"? Can "see" meaning "watch" be followed by a clause?
ex)Early in the morning of November 14, 1963, something really surprising happened several miles off the south coast of Iceland. Some fisherman were amazed to see smoke rising from the sea. They soon saw that a volcano in the sea was erupting. Hot lava and volcanic rocks came to the surface of the water....
... And the answer to your second question, keannu, is yes. (It's an interesting question; it's quite a subtle idea - that the two meanings would require different grammatical forms. But they don't in this case.)
But saw/see can also be used in the sense of realise, too. As in "Towards the end of my life I began to see the truth of the matter." It's a more abstract idea that implies "perceive" or "understand" instead of actually seeing or witnessing.