( ( Suppose ( that ( ( a ( ( negatively charged ) balloon ) ) ( is ( used ( to ( ( charge ( an electroscope ) ) ( by induction ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Suppose) (SBAR (IN that) (S (NP (DT a) (ADJP (ADVP (RB negatively)) (VBN charged)) (NN balloon)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB charge) (NP (DT an) (NN electroscope)) (PP (IN by) (NP (NN induction))))))))))) (. .)))
Suppose that a negatively charged balloon is used to charge an electroscope by induction.
(ROOT (S (NP (DT A) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN electroscope)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB study) (NP (NN charge))))))) (. .)))