题目内容：

We often think of future. We often wonder __1________ the world will be like in a hundred years’ time.

Think ___2_____ space. Perhaps a permanent station on the moon ___3_____ (set up). Perhaps people will be able to visit the moon as __4______. Cheap rockets for space travel will have been developed, __5______ (permit) long journeys through the solar system. When that time comes, people will be taking holidays in space and visiting __6_______ planets. Great progress will have been made _____7___ medicine, too. Pollution will have been controlled in a hundred years’ time.

__8________ the world will have been developed — even Antarctica. We will have used up most of the earth’s land to build our cities; __9_______ floating cities will have been built. The Japanese have already had plans of this kind. And there will be cities __10______ the sea.