( ( ( ( ( We ( ( can only ) ( ( see ( electromagnetic radiation ) ) ( in ( ( the ( ( visible light ) spectrum ) ) ( -LRB- ( ( which ( is ( why ( it ( 's ( called ( the ( ( visible light ) spectrum ) ) ) ) ) ) ) ) -RRB- ) ) ) ) ) ) ) , ) so ) ( microwaves ( are invisible ) ) ) . )
(ROOT (S (S (NP (PRP We)) (VP (MD can) (ADVP (RB only)) (VP (VB see) (NP (JJ electromagnetic) (NN radiation)) (PP (IN in) (NP (NP (DT the) (ADJP (JJ visible) (JJ light)) (NN spectrum)) (PRN (-LRB- -LRB-) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (SBAR (WHADVP (WRB why)) (S (NP (PRP it)) (VP (VBZ 's) (VP (VBN called) (NP (DT the) (ADJP (JJ visible) (JJ light)) (NN spectrum))))))))) (-RRB- -RRB-))))))) (, ,) (IN so) (S (NP (NNS microwaves)) (VP (VBP are) (ADJP (JJ invisible)))) (. .)))
We can only see electromagnetic radiation in the visible light spectrum (which is why it's called the visible light spectrum), so microwaves are invisible.
(ROOT (S (NP (PRP We)) (VP (VBP call) (NP (DT the) (JJ only) (NN light)) (SBAR (IN that) (S (NP (NNS people)) (VP (MD can) (VP (VB see) (NP (JJ visible) (NN light))))))) (. .)))