假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。
删除：把多余的词用斜线（＼）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1．每处错误及其修改均限一词;
2．只允许修改10处，多者（从第11处起）不计分。
There are bound to be question marks over our future, so we often think of future. We often wonder that the world will like a hundred years' time.
Think of space. Perhaps a permanent station on the moon will have been set up. Perhaps people will be able to visit the moon as tourist. Cheap rockets for space travel will have been developed, permitted long journeys through the solar system. When that time come, people will be taking holidays in space and visiting another planets. Great progress will have been made in medicine, too.
Pollution have been controlled in a hundred years' time.
All the world will have been developed—even Antarctica. We will have used up many of the earth's land to build our cities, therefore floating the cities will have been built. The Japanese have already plans in this kind. And there will be cities under the sea.
