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    There is a tiger and a monkey. They are friends. But one day they want to know who is stronger. One of them says, “The one who can get apples over there is stronger. ”There is a river over there. The monkey says, “I can't swim. ”The tiger says, “I can swim. Please sit on my back. ”They go across(穿过) the river. The apple trees are very tall. The tiger can't reach(够着)the apples. The monkey climbs up the tree and gets many apples. Now they know they should help each other.

香港扩建城市建设用地，采用“上天”（建设高层建筑）、“下海”（填海造地）的方式，最主要的原因是（　　）