man with him to the tower. One man left and the other stayed, but they did not 9 the bird. The crow stayed away until the second man left, too. The experiment was 10 with three men and then with four men. But the crow did not return to the nest until all the men were 11 .It was not until five men went into the tower and only four left that they were 12 able to fool the crow.Р?How good is a human’s number sense? It’s not very good. For example, babies about fourteen months old almost always notice if something is taken away from a 13 group. But when the number goes beyond three or four, the children are 14 fooled.Р?It seems that number sense is something we have mon with many animals in this world, and that our human 15 is not much better than a crow’s.Р1. A.rise B.pattern C.change D.trend
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