假定英语课上英语老师要求同桌之间互相修改作文，请你修改你同桌的以下作文。
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。
删除：把多余的词用斜线（\）划掉。
增加：在缺词处加一个漏字符号（∧），并在该词下面写出该加的词。
修改：在错的词下划一横线，在该词下面写出修改后的词。
注意：1、每处错误及修改均仅限一词。
2、只允许修改10处，多者（从11处起）不计分。
Though great progress have been made in science these years, there are still many people live in poor
conditions. They make a living by collecting or selling used things. Their children cannot go to school
because they had not enough money to send their children there. How do you think so many people still
suffer from poverty now? The answer lies the population explosion. A president of a developing country
once said, “It is us who are to blame for the poverty because of we used to ‘produce’ children without
limit. Although this few words sound simple enough, they have clear pointed out one of the causes of the
population explosion.