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：在此处加一个漏字符号（∧），并在下面写出增加的词；
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仅限一词；
2. 只允许修改10处，多者（从11处起）不计分。
Time flies! This is a third year that I have been in this school. In the past two and a half years, our school had organized many activities. What impressed me best was an activity called “Learning to Farm”. In an autumn afternoon, we were sent to a farm which we learned to plant potatoes. Having been in the city for so a long time, we were so happy to go to the countryside. After divided into three groups, we started to work. Some students cut potatoes into pieces; some dug holes, and the others put the pieces of potatoes into the hole, put the earth back and pushed them down hard. We continued doing that until all the work was done. Although we were exhausted, but we felt fulfilled on our way back home. a改为the
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(答案→)a改为the
解析：
【小题1】第三年，前面用定冠词the。
【小题2】表示自过去某一时刻到说话时这段时间中的经历，用现在完成时，所以had 改为has。
【小题3】这里表示给我印象最深的活动是，所以best 改为most。
【小题4】在一个秋天的下午，应该说On an autumn afternoon。
【小题5】这里含有一个定语从句，且关系词在从句中作地点状语，所以which改为where或前面加on。
【小题6】such后跟名词，所以so 改为such。
【小题7】“我们”和“分成三组”是被动关系，故用现在分词的被动式。
【小题8】根据the pieces of potatoes，所以hole用复数。
【小题9】这里是单数，所以them改为it。
【小题10】Although与but不能连用，所以去掉but。