已知平面α，β，γ，直线l，m满足：α⊥γ，γ∩α=m，γ∩β=l，l⊥m，那么①m⊥β； ②l⊥α； ③β⊥γ； ④α⊥β．
可由上述条件可推出的结论有______（请将你认为正确的结论的序号都填上）．
若α⊥γ，γ∩α=m，γ∩β=l，l⊥m，
由于β⊥γ不一定成立，故①m⊥β、③β⊥γ错误；
根据面面垂直的性质我们可得l⊥α，即②正确；
再由面面垂直的判定定理可得α⊥β，即④正确；
故答案为：②④．
One day a stranger came to the nearest village and asked where he could find wild pigs. Somebody told him, and he went off. He had no 36 with him, and the village people 37 what he was going to 38 with the pigs. When he came back a few months later and said that he had 39 all the pigs, the villagers were still more surprised, but some of them agreed to go with him 40 he asked for help in bringing the pigs out. They wanted to see whether he was telling 41 . They soon discovered 42 he was. All the pigs were inside the enclosure(围栏) which had a fence round it and a 43 in one of its sides. “44 did you do it?” they asked the stranger. “ well, it was quite easy really,” he answered. “ I began by 45 some Indian corn. 46, they would not touch it, but after a few weeks, some of the younger pigs 47 to run out of the bushes, take some of the corn quickly, and then run back. Soon all the pigs were eating the corn I 48 out there. Then I began to build a fence round the corn. At first it was very 49, but little by little I built it higher and higher without 50 the pigs away. When I saw that they were 51 me to bring the corn each day 52 going and searching for their own food 53 they had done in the past, I can 54 one day while they were all eating inside the enclosure. I can catch any animal in the world in the same way if I can get it into the habit of 55 me for its food.
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