[解析]
Dear Mr.Principal,
I learned the news on TV that an accident was happened to the Chinese students in a PE class.I suggest that our school organizes a first aid course, that is very useful.The reasons why a first aid course is necessary are as follows:we students lack first aid knowledges.A first aid course can't satisfy our need. Beside,it will give information about many situations and give us the chance to practice first aid treatments.
As for the course, they can be given monthly.The course should main include the practice of first aid treatments.It would∧ better if the experts in first aid were introduced to instructing the course.
详解;
1.去掉was.考查动词.happen是动词"发生"不能有被动结构.
2.organizes改成organize.考查虚拟语气.suggest作为"建议"讲引导宾语从句,从句用should+动词原形,should可以省略.
3.that改成which.考查定语从句.本句是非限制性定语从句,which引导非限制性定语从句.
4.knowledges改成knowledge.考查名词的数.knowledge是不可数名词,所以不与s连用.
5.can't 改成can.考查动词.根据句意:急救课程能满足我们的需要.因为前文指出我们缺乏急救知识,所以改成肯定.
6.Beside改成Besides.考查介词.根据句意:另外,它会给我们带来很大的帮助.beside是介词"在…旁边",besides"另外,此外".
7.they改成it.考查代词.这里指这门课程,所以用it引导.
8.main改成mainly.考查副词.此处用副词修饰动词include,所以用mainly.
9.加be.考查固定句型.It would be better if…是英语的固定句型"如果…将非常好".
10.instructing改成instruct.考查非谓语.动词不定式to后跟动词原形.