帮我改改语法

问题描述:

帮我改改语法
My recent three summers were spent on summer school.In 2007,I was offered a free course to imporve English skill.Since I took ESL course in Grade 10,I have to complete my ELA course during the summer of 2008.Last summer,I took English course in summer school again to prepare for my English language proficiency test.I believe this summer I will go travelling since all periodic tasks have been completed.
我这是描写最近几个夏天做了什么,各位帮我找找语法错误,尤其注意介词,to,for,on之类的,或者有什么能让这篇看起来更正式的改法,哪怕一个词也行,

My recent three summers were spent in summer school.
此处应将on改为in,因为on后面的地点一般是平面的,或者是露天的,而summer school是立体的,并且是个建筑
Since I took ESL course in Grade 10,I had to complete my ELA course during the summer of 2008.
此处应将have改为过去时had,因为在同一句句子中,前后时态要保持一致
其他没什么问题了.