词根：-grat-

【词根含义】：高兴,恩惠

【词根来源】：来源于拉丁语形容词gratus(令人愉快的)、gratiosus(令人愉快的)和名词gratia(愉快,恩惠)。

【同源单词】：agree, agreeable, agreement, congratulate, congratulation

前缀：il-, in-, ir-, im-

【词根含义】：不,无,非;入,向内

【词根来源】：(il-用于l前;im-用于b, m, p前;ir-用于r前;in-用于其它情况)   来源于拉丁语in。

【同源单词】：illegal, illegality, illegitimate, illiterate, illogical

词根词缀：grat-, gra-, grac-

【来源及含义】Latin: beloved, pleasing, dear, agreeable; grateful, thankful, pleased

【同源单词】agree, agreeable, agreeableness, agreeably, agreement, congratulate

词根词缀：-tude

【来源及含义】Latin: a suffix; state, quality, condition of

【同源单词】acritude, altitude, altitude, amplitude, amplitude modulation, aptitude