Conjunction after a linking verb

[ronmecer]

Thanks to all of you! especially TheParser

So, here "because" and "as" are used to introduce a noun clause (noun clause as a subject complement), but my grammar books just say words like when, where, why, how, who, whom, what, which, whose, that, whether, if, whatever,whenever, whomever, however can introduce a noun clause, but don't mention "because" or "as".

Does anybody have any ideas on this?

[philo2009]

Thanks to all of you! especially TheParser

So, here "because" and "as" are used to introduce a noun clause (noun clause as a subject complement), but my grammar books just say words like when, where, why, how, who, whom, what, which, whose, that, whether, if, whatever,whenever, whomever, however can introduce a noun clause, but don't mention "because" or "as".

Does anybody have any ideas on this?

Yes. How about buying a new grammar book?