文章也要有其主题句。否则会给人造成“群龙无首”之感。如果故意把主体隐藏在文章之内，容易造成不知所云的情况。所以大家在写作时一定要写一个主题句，放在文章的开头(保险型)或者结尾，让读者一目了然。特别提示：隐藏主体句可是要冒险的! To begin with, you must work hard at your lessons and be fully prepared before the exam(主题句). Without sufficient preparation, you can hardly expect to answer all the questions correctl