( ( In ( ( a lot ) ( of cases ) ) ) ( , ( ( ( all ( the ( valence electrons ) ) ) ( of ( ( all ( the atoms ) ) ( of ( the material ) ) ) ) ) ( ( ( are ( in ( Fermi ( energy levels ) ) ) ) ( below ( the ( conduction band ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NP (DT a) (NN lot)) (PP (IN of) (NP (NNS cases))))) (, ,) (NP (NP (PDT all) (DT the) (JJ valence) (NNS electrons)) (PP (IN of) (NP (NP (PDT all) (DT the) (NNS atoms)) (PP (IN of) (NP (DT the) (NN material)))))) (VP (VBP are) (PP (IN in) (NP (NNP Fermi) (NN energy) (NNS levels))) (PP (IN below) (NP (DT the) (NN conduction) (NN band)))) (. .)))
In a lot of cases, all the valence electrons of all the atoms of the material are in Fermi energy levels below the conduction band.
(ROOT (S (NP (NP (NNS Electrons)) (PP (IN in) (NP (NP (DT the) (JJ outer) (NN energy) (NN level)) (PP (IN of) (NP (DT an) (NN atom)))))) (VP (VBP are) (VP (VBN called) (NP (JJ valence) (NNS electrons)))) (. .)))