疑问限定词可以引导特殊疑问句，也可以引导名词性疑问分句（或称为间接疑问句）。wh-词保持疑问意义。分句本身是个问句。

融合型关系限定词引导名词性关系分句。wh-词没有疑问含义。分句相当于一个名词词组。

Which design is the best must be tried in practice.

这个which分句是名词性疑问分句，which为疑问限定词。分句本身是个问题：Which design is the best? 哪种涉及最好？这要在实践中尝试/验证。疑问句作主语就是名词性疑问分句，只需将特殊疑问句去倒装、去问号即可。

Whichever team gains the most points wins.

这个whichever分句是名词性关系分句，whichever是融合型关系限定词。whichever team=the team that. 分句相当于一个名词词组被限制性定语从句修饰。wins的主语是the team.

Which/what book do you like ?

Whose bag is this? 

以上二句中的which，what, whose都是疑问限定词，引导特殊疑问句。

所有的疑问词（包括疑问限定词）都可以引导特殊疑问句（即你说的简单句或者称为直接问句），也可以引导名词性疑问分句（或称为间接疑问句）。例如：

Tell me which book you like.

Tell me whose bag this is.

疑问限定词和融合型关系限定词的区别在于：

1 前者有疑问含义，后者没有疑问含义；

2 前者引导名词性从句时，这个问句在主句中作成分。例如 Which design is the best整个问句的内容是主语。must be tried是针对问句内容的。

3 后者引导名词性关系分句时相当于一个名词词组，即真正在主句中作成分的是限定词所修饰的那个名词。例如whichever team gains the most points，真正做主语的是team, 谓语动词wins的主语是the team.

4 疑问限定词可以引导特殊疑问句，例如：Which design is the best? 而融合型关系限定词不能引导独立分句，Whichever team gains the most points. 这是错误的。因为该分句只相当于一个名词词组。

疑问限定词which，whose通常是针对this，that，his，our，Tom's等提问的。例如：

This car is the best. Which car is the best?

This is my book. Whose book is this?

所以，which和whose为特指限定词。

what通常就事物的种类提问，例如：What are you reading? I am reading a book. What are you eating? I am eating an apple. 所以通常认为what为泛指限定词。但这不是绝对的。融合型关系限定词what则为特指限定词：I gave him what money I had with me.