( ( ( ( ( ( A ( wide variety ) ) ( of instruments ) ) , ) ( including ( ( ( ( ( ( precise spirit-levels ) , ) ( electronic ( `` tiltmeters ) ) ) , ) and ) ( electronic-laser ( beam instruments ) ) ) ) ) , ) ( ( can ( ( ( measure changes ) ( ( ( in ( ( the ( slope ( or ( `` ( tilt '' ) ) ) ) ) ( of ( the volcano ) ) ) ) or ) ( in ( vertical ( and ( horizontal distances ) ) ) ) ) ) ( with ( ( a precision ) ( of ( ( ( only ( a few ) ) parts ) ( in ( a million ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (JJ wide) (NN variety)) (PP (IN of) (NP (NNS instruments))) (, ,) (PP (VBG including) (NP (NP (JJ precise) (NNS spirit-levels)) (, ,) (NP (JJ electronic) (`` ``) (NNS tiltmeters)) (, ,) (CC and) (NP (JJ electronic-laser) (NN beam) (NNS instruments)))) (, ,)) (VP (MD can) (VP (VB measure) (NP (NNS changes)) (PP (PP (IN in) (NP (NP (DT the) (NN slope) (CC or) (`` ``) (NN tilt) ('' '')) (PP (IN of) (NP (DT the) (NN volcano))))) (CC or) (PP (IN in) (NP (JJ vertical) (CC and) (JJ horizontal) (NNS distances)))) (PP (IN with) (NP (NP (DT a) (NN precision)) (PP (IN of) (NP (NP (QP (RB only) (DT a) (JJ few)) (NNS parts)) (PP (IN in) (NP (QP (DT a) (CD million)))))))))) (. .)))
A wide variety of instruments, including precise spirit-levels, electronic &quot;tiltmeters, and electronic-laser beam instruments, can measure changes in the slope or &quot;tilt&quot; of the volcano or in vertical and horizontal distances with a precision of only a few parts in a million.
(ROOT (S (NP (NNS Tiltmeters)) (VP (VBP are) (VP (VBN used) (S (VP (TO to) (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))))))))))) (. .)))