Complex sentence: By enhancing and overlaying frames, he found what appeared to be the rear body of a creature underwater: Before I saw the film, I thought the Loch Ness Monster was a load of rubbish.
Split into simpler sentences: By enhancing and overlaying frames, he found what appeared to be the rear body of a creature underwater. He commented, Before I saw the film, I thought the Loch Ness Monster was a load of rubbish.