词根词缀：penta-, pent-, pente-, pento-

【来源及含义】Greek: five; a number used as a prefix

【同源单词】molybdenum pentachloride, pentacanth, pentacanthous, pentachord, pentacle, pentactinal

词根词缀：valid-, val-, vale-, -vail, -valent, -valence

【来源及含义】Latin: valere, to be strong, to be well, to be worth; strong; power, strength; and "fare well" [go with strength]

【同源单词】Ab abusu ad usum non valet consequentia, Ab actu ad posse valet illatio, ad valorem, Aeternum vale, ambivalence, ambivalent