首先表示自己的梦想是什么,表态自己会实现的决心
I have a dream to become ...becuase I think the job is very meaningful.I will work hard to realize it.
第二段可以写自己如何实现（自己进行发挥连贯）
连接性的短语有：
I will try my best to come it true.1.For I am young,it is import to study well so that I have the knowlege and ability to teach others.2.excerise---to have a good health is a precondition to succeed.3.enrich my knowledge and have the wide vision
最后写自己相信通过努力一定能成功
I will work hard until my dream come true and I believe I will be a good...