短文改错(共10小题；每小题1分，满分10分）
文中共有10处语言错误，每句中最多有两处。错误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( ∧ ），并在该词下面写出修改后的词。
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仅限一词；
2.只允许修改10处，多者(从11处起）不计分。
Great changes have been taken place in my village. Ten years ago, the small and low houses, which lie on the north of a lake, produced much waste. As the result, the lake was serious polluted. To the west was a sandy field, that was the source of dust. Better still, a brickyard on the southwest side of the lake used up a great deal good soil. Now the poor house have been replaced by green trees and the brickyard by tall buildings. The sandy field that the villagers used to ploughing has been covered with fruit trees. On the lake the villagers often spend his spare time boating and fishing.