继名词性从句的基本概念学习之后，必须要分清楚的就是名词性从句的引导词。
引导名词性从句的连接词分为三类：单纯连接词、连接代词、连接副词。
1、单纯连词：that（没有意义，不占成分，仅起到引导作用，引导宾从时可省略）
whether/if（有意义表“是否”，不占成分）
例1. That he passed the exam made us happy.（that引导主从）
例2. He said that you should study hard.（that引导宾从）
例3. The problem is that we lack money.（that引导表从）
例4. The news came that he won the game.（that引导同位语从）
例5. Whether it is true remains a question.（whether引导主从，表“是否”）
例6. We don’t know whether/if he is ready.（whether/if引导宾从，表“是否”）
例7. I’m interested in whether you have accepted his flower.（whether引导宾从，表“是否”）
例8. The question whether the work was worth doing has not been decided.（whether引导同位语从，表“是否”）
2、连接代词：what， who, which, whose，whatever, whoever, whichever
例1. What worries us most is who let out the secret.(what引导主从，且在主从中充当主语；who引导表从，且在表从中充当主语)
例2. The new comer went to the library the other day and searched for whatever he could find about Mark Twain.(whatever引导宾从，且在宾从中充当宾语)
例3. The question who should do the work requires consideration.(who引导同位从，且在同位从中充当主语)
例4. The place isn't what it used to be.(what引导表从，且在表从中充当表语)
3、连接副词：when, where, why, how
例1. Why he did that wasn't quite clear.（why引导主从，且在主从中充当原因状语）
例2. I hate it when they talk with their mouth full of food.(when引导宾从，且在宾从中充当时间状语)
例3. This is where we found the interest.(where引导表从，且在表从中充当地点状语)
例4. I have no idea why she quit her present job.(why引导同位从，且在从句中充当原因状语)
小伙伴们，关于名词性从句的引导词的初步学习就到这里了，完全掌握这些引导词在四种不同名词性从句中的用法仍需刻苦练习！
