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l0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仅限一词；
2．只允许修改l0处，多者(从第11处起)不计分．
Last summer , I had a unforgettable experience. It happened on my uncle’s farm which there are
many flowers. In a Saturday morning, we heard a great noise coming outside. Looking out the window,
I saw a mass of bees flown above the farm. There were too many bees that the whole farm seemed dark.
We were very frightening. For some moments, the bees advanced our house. My uncle were dragged
me into the back room which was very dark. We covered us with a blanket, shaking with fear. A few hours later,
we came out of the back room and found the bees had flown away.