Can a fish hear fishermen moving along the stream? What are the facts about the ability of a fish to see? Can they tell the difference between colors? The sharp hearing of a fish has been proved by two scientists, who trained a fish to expect its food when it heard the sound of a whistle. And a slight sound two hundred feet away could drive fishes away. That should make fishermen start thinking. One scientist had made experiments to prove fish can recognize different colors such as red, brown, yellow and green. Fish also have an eye for different shapes. One scientist proved this by teaching fish to connect certain patterns with food. He used a small circle and a square. If the fish swam towards the circle, they received food as a reward. If they swam towards the square, they received nothing. The fish learned in time to go to the circle but not to the square. Does this mean that in time fish might learn to leave alone all food on hooks that they have seen often before? Here is something for all fishermen to think about! These facts help to make more believable some of the “believe it or not” stories that have been told about fish. It is clear that fish have sometimes shown their ability to gain knowledge as man does. A good example of what we might call “thinking” by a fish is given by an experience of Dr. Andrew Gage. Fishing over a bridge, he hooked a fish. It struggled and dragged the line two hundred feet away before he stopped it. Then it swam back to the bridge. The clever fish then swam round a pile and, with a sudden push, broke the line. If the story ended there, one could say that the fish had freed itself by chance. However, Gage went on fishing. Below him he could see the fish that had broken loose. After another twenty minutes the fish again seized the food on the hook. This time it did not swim out but swam round one of the piles and again broke the line. Many stories are told of the fish that get away and the clever “old hand” ones that can’t be caught. The more often a fish is nearly caught, the more difficult it will be to interest it next time. 小题1:The last two paragraph’s mainly discuss _________.
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