If the cloth has tension before it is cut, then it will contract after it is cut into separate pattern pieces.
( ( If ( ( the cloth ) ( has ( tension ( before ( it ( is cut ) ) ) ) ) ) ) ( , ( then ( it ( ( will ( contract ( after ( it ( is ( cut ( into ( separate ( pattern pieces ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (DT the) (NN cloth)) (VP (VBZ has) (NP (NP (NN tension)) (SBAR (IN before) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN cut))))))))) (, ,) (ADVP (RB then)) (NP (PRP it)) (VP (MD will) (VP (VB contract) (SBAR (IN after) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN cut) (PP (IN into) (NP (JJ separate) (NN pattern) (NNS pieces))))))))) (. .)))
Cloth will expand upon cutting it when tight.
( Cloth ( ( will ( ( expand ( upon ( cutting it ) ) ) ( when tight ) ) ) . ) )
(ROOT (S (NP (NNP Cloth)) (VP (MD will) (VP (VB expand) (PP (IN upon) (S (VP (VBG cutting) (NP (PRP it))))) (SBAR (WHADVP (WRB when)) (S (ADJP (JJ tight)))))) (. .)))