國有其君，家有其主，文章也要有其主。一個主題句放在文章的開頭(保險型)或者結尾，讓讀者一目了然，也會讓你在寫作文時有個參考，不跑題。
特別提示：隱藏主體句可是要冒險的!
To begin with, you must work hard at your lessons and be fully prepared before the exam(主題句). Without sufficient preparation, you can hardly expect to answer all the questions correctly。
