offers an intriguing what-if premise 
(ROOT (S (VP (VBZ offers) (NP (DT an) (JJ intriguing) (SBAR (WHADJP (WP what) (HYPH -) (IN if)) (NN premise))))))
(ROOT (S (VP (VBZ ) (NP (DT ) (JJ ) (SBAR (WHADJP (WP ) (HYPH ) (IN )) (NN ))))))