prerequisite = something required (something needed to happen)

　　rather = instead 相反地/ in some degree在tain

　　sank (sink的過去式)= descended; dropped to the bottom

　　scant = minimum

　　sited = located

　　sophisticated = refined /elaborated /complex

　　ubiquitous 到處存在的 = common

　　unanimity = total agreement

　　spectator = viewer

　　sporadic = intermittent /irregular

　　stylus 鐵筆，針狀物 = pen

　　unconceivable = unimaginable

　　uniformly = evenly/ without variation/consistently

　　unique = sole/ distinct

　　warranted = authorized 授權(quán)的/justified

　　assume=take on 呈現(xiàn)/ suppose, posit 假設(shè)

　　foster=promote ，encourage

　　Plumage羽毛=feather

　　Composition作文，成分，混合物=mixture

　　relatively=comparatively

　　substitute=replacement

　　premise= assumption

　　within= inside

　　have nothing to do = in no relation to

　　vigorous= strong

　　scope=extent