B1 READING PART6 EXERCISE4

In 1995, some scientists were working under the sea in Japan, when they saw some something very strange. They had found circular patterns on the sandy ocean floor, and they had (1) idea where they had come from. Who could have made these carefully created circles, and why had they (2) made? They were all different sizes, and some were more (3) 2 m wide. They studied the problem for a while and discovered that the circle-makers (4) lonely male pufferfish. These little fish made (5) circles to get female pufferfish to come and live with them. Nobody had known about these circles until these scientists found them, and now people are studying the circles, (6)  the little fish that make them.

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