( ( All ( of them ) ) ( ( require ( ( a way ) ( to ( measure ( tilt angles ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT All)) (PP (IN of) (NP (PRP them)))) (VP (VBP require) (S (NP (DT a) (NN way)) (VP (TO to) (VP (VB measure) (NP (NN tilt) (NNS angles)))))) (. .)))
All of them require a way to measure tilt angles.
(ROOT (S (NP (NP (NNP Instruments)) (SBAR (WHNP (WDT that)) (S (VP (VB measure) (NP (NP (DT the) (NN angle)) (PP (IN of) (NP (NP (DT the) (NN slope)) (PP (IN of) (NP (DT a) (NN volcano)))))))))) (VP (VBP are) (VP (VBN called) (NP (NN tilt) (NNS meters)))) (. .)))