3、可写性,所定的主题不能太笼统,也不能太具体。Example:In Hemingway’s story ”Soldier’s Home,“Krebs tells his mother that he wants no part of God’s Kingdom.这个句子太具体以至于无东西可写,无法展开段落。Example:In Hemingway’s story “Soldier’s Home”,Krebs is a lonely,cynical veteran.这个句子可作为主题句,因为可以围绕“lonely,cynical”