修改后文章：（加括号的为修改部分）
Our school is looking for （an） English teacher to teach senior high( school )stundents.If you want,you can choose three of the following four courses:Speaking,Writing,Britian Today,American Today.And work 12 hours a week.Besides,you (can also ) work as an advisor (in) our students' english club or (newspaper).
仅仅是自己的见解,有意见欢迎随时提出,我一定竭尽全力,新年快乐