formation

n.组织，形成物；构成；地岩层

forgiving, forgivingly, forgo, forgot, forgotten, fork, forlorn, forlornly, forlornness, form, form-blaind, formal, formaldehyde, formalin, formalism, formality, formalization, formalisation, formalize, formalise, formally, format, formative, formed, former, formerly, formic acid, Formica, formidable, formidably, formless, formlessly, formula, formulaic, formulate, formulation, fornicate, fornication, forsake, forsaken, forseeable, forswear,