iota是希臘字母表中第9個字母"I"的名稱。not an iota of 出自《新約。馬太福音》第5章："律法的壹點壹畫都不能廢去，都要成全。"因為iota是希臘字母表中最小的壹個字母，它有時可以寫作壹短橫置於其他字母之上；遺漏這壹點點對發音並無什麽影響，只按規則不能減少而已。《福音書》所說的律法，系指"摩西律"，意即無論何人都不允許隨便廢去這戒律哪怕是最小的壹條，甚至其中的壹個字母，壹個小小短橫也不得更動或遺漏。
由此，在語言中遺留下來這個成語，轉義表示not a bit of ;not one jot or little; not at all等意思。iota在這裏，相當於漢語"小不點兒"的意思。
Eg: Science deals with things in a practical way. Science means honest, solid knowledge, allowing not an iota of falsehood, and it involves Herculean efforts and grueling toil.
There is not an iota of truth in the story.
20.The Salt of the Earth社會中堅；民族精華；優秀份子
The Salt of the Earth這個成語，字面意思"世上的鹽"
鹽是飲食中不可缺少的調味品，人體若缺鹽，健康就會受到影響，出現種種疾病。鹽還有殺菌、解毒、消炎、除汙等多種功用，它既是"百藥"，又是工業之母，確是值得珍視的東西。在許多民族的習俗匯總，鹽被當作敬客的高貴禮品。
The Salt of the Earth壹詞出自《聖經》，據《新約。馬太福音》（Matthew）第5長記載：耶穌對他的門徒說:"Ye are the salt of the earth: but if the salt have lost his savor, wherewith shall it be salted? " 在這裏，salt用於轉義，表示flavor；of the earth即of the world。這是耶穌登山垂訓論"福"，所講福音結尾的話，他把門徒比做"世上的鹽"，這是極高的稱贊。這句話在後世不斷引用變成了壹個典故性成語，轉義為the most valuable members of society; the finest type of humanity; a person or a group of people having the best character 之意
eg: He does a lot of good jobs and is considered to be the salt of the world.
You all are the salt of the earth. Our hope is placed on you
21.Cast pearls before swine對牛彈琴；白費好意
To Cast pearls before swine的意思是"珍珠投在豬玀前面"。swine是個舊詞，書面詞，即今為pigs,不過swine單復同行，本句為復數。
這個成語源自《新約。馬太福音》第7章："Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you".由於to cast pearls before swine,比喻確切，在後世不斷引用中而成為壹個國際性成語，常用來表示to offer sth valuable or beautiful to those who can't appreciate it; to give what is precious to those who are unable to understand its value等意思，含有輕蔑嘲笑色彩。按其字面意義，這個成語與漢語成語"明珠按投"相似，但是寓意不同，基本上不對應；按壹比喻意義，它相當於"對牛彈琴"，"向驢說經""壹番好意給狗吃""狗咬呂洞賓，不識好人心"等。
She read them Shakespeare, but it was casting pearls before swine
I won't waste good advice on John any more because he never listens to it.I won't cast pearls before swine.
……and when I let the upper floor to Cap'en Cuttle, oh I do a thankless thing, and cast pearls before swine
22.a wolf in sheep's clothing批著羊皮的狼；貌善心惡的人
耶穌在加利利壹帶傳道布教，收了很多信徒。有壹天，他對門徒說:"Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves"
eg: Mrs. Martin trusted the lawyer until she realized that he was a wolf in sheep's clothing
One who teaches morality and practises immorality is a wolf in lamb's skin
23.separate the sheep from the goats區別好壞，分清良莠
《新約。馬太福音》記述："And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divides his sheep from the goats"
由於《聖經》的影響，sheep和goat在英語中的形象截然不同，前者比喻好人，後者比喻壞人。英語中有關goat的成語，大多貶義。如：to play the goat=play the fool（瞎胡鬧）；to get sb's goat（觸動肝火） ；等等。《聖經》說牧羊人要分辨綿羊和山羊，"把綿羊安置右邊，山羊左邊"。據說野山羊常混進羊群裏，引誘綿羊，故牧養人必須把它們區分開來，以免混淆。
由此，人們用to separate the sheep from the goats這個成語，來比喻to separate the good from the wicked; to divide good or useful people from bad or useless
eg: We'll go through the list of members, and separate the sheep from the goats
Have faith in me, please. I can separate the sheep from the goats