( ( ( ( ( ( ( Drought , ) rain ) , ) drought ) , ) rain ) . )
(ROOT (NP (NP (NNP Drought)) (, ,) (NP (NN rain)) (, ,) (NP (NN drought)) (, ,) (NP (NN rain)) (. .)))
Drought, rain, drought, rain.
(ROOT (S (NP (NNS Droughts)) (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (EX there)) (VP (VBZ is) (ADJP (JJ little) (PP (TO to) (NP (NP (DT no) (NN rain)) (PP (IN in) (NP (NP (DT a) (NN period)) (PP (IN of) (NP (NN time)))))))))))) (. .)))