unfortunately, unimportant, unlike, unload, unusual, unaware, enlightened, unparalleled, unsustainable,

　　7) non- (not) nonsmoker, nonexistence, non-cooperation, nonstop, nonmetal, nonresident, nonsense, nonfundamentalist, nonspecialist

　　8) mis- (wrong, wrongly) misjudge, misunderstand, mislead, misspell, misstep, misfortune, misuse, misguided, misinformation

　　9) de- (showing the opposite, to remove, to reduce) deform, deface, demobilize, destruction, defore

st, denationalize, depress, depression, devalue, decode, decrease, degenerate , degrade , descend, descendant , descent

　　10) pre- (before, in advance) prefix, pre-historic, precaution, precede , preceding, preclude , predecessor , predict, predominant , preface, prejudice, preliminary, premature , premier , premise , premium , preparation, prepare, prepay, preside , president, presumably, presume , pretext , prevail, prevent, previous, prewar, preconception, prediction, prescientific, presumptively

　　11) ante-, (before, in advance) anteroom, ante-Christian, antemeridian, anticipate, antique

　　12) fore- (in advance, before, in or at the front) forearm, forehead, foreman, foretell , foresee , forefather , foreleg, forerunner , fore , foremost, forecast, forewarn

　　13) ex- (out, out of, former) ex-minister, ex-president, ex-Soviet Union, ex-wife, export, exclude, exclusive, excursion, exhibit, exile , exit, exotic , expand, expansion, expedition , expel , expend , expenditure , expense, explode, explosion, explosive, expose, exposition , exposure, express, expression, extend, extension, extensive, exterior, external, extinct, extra, extract

　　14) post- (later than, after) postgraduate, postwar, postmeridian, postpone, postscript

　　15) sub- (under, below, less important) sub, subject, subway, subtitle, subdivide, submarine , sub-zero, submerge, submit, subordinate , subscribe , subsection, subsequent, subsidiary , subsidy , substance, substantial, substitute, subtract, suburb, subconsciously, subtly