subsoil

n.下层土,底土

subsection, subsequence, subsequent, subsequent to, subsequently, subservience, subservient, subserviently, subside, subsidence, subsidiary, subsidization, subsidization, subsidisation, subsidize, subsidize, subsidise, subsidy, subsist, subsistence, subsistence crop, subsistence level, subsonic, substance, substandard, substantial, substantially, substantiate, substantiation, substantive, substantively, substation, substitute, substitute for, substitute...for, substitution, substratum, substructure, subsume, subtenancy, subtenant, subtend,