一知半解最危險
A little learning is a dangerous thing 一知半解最危險，因為略有知識的人往往不自覺無知，很容易被不真實的言論欺騙。
Learn 跟 study 的意思相近，但用途廣泛得多。
Study 的涵義比較清晰和確切，不外乎兩個：1. 學習；用功，to look at, read, or listen to something in order to learn。2. 研究；注意看；仔細端詳，to examine carefully。A quick study 卻可以指一個人，例如：He’s a quick study and he easily grasps all the details of a discussion 便是指這個人的學習能力很高，很快掌握到問題的核心：he is able to learn things quickly. A quick study is one who is able to memorize something easily and quickly or is able to understand and deal with something easily and successfully.
Learn 的涵義，最少有三個：
1. 學習 to gain knowledge or skill：You’ll take time to learn the ropes. You learn the ropes means you learn the details and the procedure of a craft; you are thoroughly familiar with a particular situation. 例如你學習一門工藝，學曉做法的過程，the ropes of a business or trade；你掌握竅門，學會基本的技巧和要領，慢慢熟悉某個行業的操作。這句習用語，源自帆船上的水手，他們需要學會怎樣擺弄好桅繩，如何操縱由桅繩製成的種種複雜索具，往往需要累積經驗。
2. 記住 to fix in the memory；例如：learn by heart 記住、背誦出來，you learn so thoroughly that you can repeat from memory; you memorize something, so that it can be instantly recalled. Children had to learn their mathematical tables by heart，中國的小朋友，從小需要背誦乘數表；我們假如能夠背誦一些唐詩宋詞，對語文會很有幫助，一生受用。When we were at school, we had to learn a poem by heart every week.
3. 得悉 to become informed：His father learnt in the newspapers of his son’s success in sports 他的父親從報章得悉兒子在體育上的成就。
活到老，學到老
Learn 的習用語還有：learn a lesson/learn one’s lesson 汲取教訓，often after a mistake，通常指在一次不幸事件或犯了錯誤之後，知道下次應該怎樣做，或者曉得不去幹。You live and learn 活到老，學到老：you gain useful experience with age; you learn through experience. You learn something the hard way: you learn something through your own bitter experience 通過自己的痛苦經驗而學到的東西。
Know 的習用語更多更廣泛，其熱門例子如下：
know a thing or two 明白事理，精明能幹；
know all answers 萬事通，什麼都知道；
know one’s stuff 很內行；
know somebody through and through 徹頭徹尾認識某人；
know what one is talking about 學識淵博，知識豐富；
know a man by his company 從其交友，可判斷其為人；
know something backwards and forwards 對某件事情 知道得很多；
know something inside and out 對某事透徹暸解；
know something like the back of your hand 對某事瞭如指掌。
已知的危苦比未知的好
還有一句很有趣的諺語：better the devil you know than the devil you don’t，這句話有不同的詮釋，便有不同的翻譯。知道的壞事或壞人比不知道的好：it is better to deal with a person or thing you know, even if you do not like them, than to deal with a new person or thing who could be even worse，例如：I know my boss can be difficult to work with sometimes, but better the devil you know. 諺語中的 devil 可以解作危險 danger 和困苦 hardship，所以也有人這樣翻譯：已知的危苦比未知的好；所謂明槍易躲，暗箭難防，例如；一個怕暈船的人，寧願坐船而不坐飛機，因為暈船的痛苦，他早已體驗過了，坐飛機難以忍受的滋味，卻是未知數。
Knowledge 作為 know 的名詞，有幾個意思：
1. 知識、學問、學識 learning；that which is known，例如：medical/scientific/practical knowledge 醫學、科學、實用知識。Knowledge is power 知識就是力量。
2. 了解 understanding；the condition of knowing，例如：He has little knowledge of the facts 對於事實的真相，他了解得很少。
3. 熟悉 familiarity with；information about something，例如：He has a good knowledge of Vancouver 他對温哥華這個地方很熟悉。
經常用到的 knowledge idiomatic expressions 有：
come to someone’s knowledge 被某人發現；
to my knowledge/to the best of my knowledge 據我所知；
without my knowledge 我毫不知情。
常見的搭配 knowledge collocations 有：common/general/wide/extensive/basic/full/expert/specialized/intimate/profound knowledge。
本專欄逢周二、五發表
