听力题 Perhaps the most unusual animal ever brought to Australia was the cane toad. It is a large and ugly species of toad and was imported to this country by the sugar cane farmers in 1935 to get rid of the beetle which kills the sugar cane plant. The cane beetle is the natural enemy of the sugar cane plant. It lives in the cane and drops its eggs onto the ground around the base of the cane. The eggs develop into worms and then the worms eat the roots of the cane, resulting in the death of the plant. In the mid 30s there was a serious outbreak of the cane beetle and the farmers became desperate to get rid of the pest which was ruining their livelihood. Meanwhile it was reported that a toad, native to Central America, had been taken to Hawaii, where cane is also grown, and introduced with apparent success. So the Australian farmers arranged to import one hundred loads from Hawaii. The toads were then released into the cane fields to kill the cane beetle. As predicted, the toads started to breed successfully and within a very short time their numbers had swollen. But there was one serious problem. It turned out that cane toads do not eat cane beetles. And the reason for this is that toads live on insects that are found on the ground and the cane beetle live at the top of the cane plant well out of reach of the toads. In fact they never come into contact with each other.