a lower i.q. than when i had entered 
(ROOT (NP (NP (DT a) (JJR lower) (NN i.q.)) (PP (IN than) (SBAR (WHADVP (WRB when)) (S (NP (PRP i)) (VP (VBD had) (VP (VBN entered))))))))
(ROOT (NP (NP (DT ) (JJR ) (NN )) (PP (IN ) (SBAR (WHADVP (WRB )) (S (NP (PRP )) (VP (VBD ) (VP (VBN ))))))))