<!<del>StartFragment&gt;<br/><br/>WHEN, WHERE, WHY and HOW are an interrogative adverb while being conjunction also it can be a noun clause <br/><br/>So WHEN clause, WHERE clause, WHY clause and HOW clause can be a subject, an object, a complement & an object of the preposition<br/><br/>easily, I can find those play role as an object & an object of the preposition<br/><br/>But it is hard to find those play role as a subject.<br/><br/>so I made some sentences below please check my sentence it correct or not<br/><br/>And if you have some time please give some sample sentences....<br/><br/>1.Who killed him is unknown. <br/><br/>2.when he will come is unknown.<br/><br/>3.how he solved that question is miracle.<br/><br/>4.why Courtney Killed Kurt has been mystery.