用心提防、別出錯
核心這一家：把心思壓在事情上、提防出錯。從自己做事謹慎，到叫別人「小心！」，再到「再小心也不為過」，都是同一份戒備的注意力，只是說話的角度不同。
cautious, trying not to err · adjective · A2
Trying hard not to make a mistake, or not to hurt, break, or lose something.
小心 / 謹慎
核心畫面
Picture someone handling something with their whole mind on it — carrying a full cup, on ice — so that nothing goes wrong. To be careful is to be full of that watchful, don't-let-anything-slip attention.
可以想成：一個人把整顆心都放在手上的事情上——端著滿滿一杯水、踩在結冰的路面——就為了不讓任何差錯發生。carefu…更多收起
可以想成：一個人把整顆心都放在手上的事情上——端著滿滿一杯水、踩在結冰的路面——就為了不讓任何差錯發生。careful 就是滿滿一身這種提防、放不下的注意力。From the word’s history
Careful is care + -ful, 'full of care.' Old English caru meant 'sorrow, anxiety, a weight on the mind' — so being careful was literally being full of that anxious mental attention. The worry later turned into watchful heed: minding something so it stays safe.
careful 是 care +「-ful（充滿）」，字面就是「充滿 care」。古英語的 caru 原指「憂愁、掛心、心上的重擔」，所以 careful 本來就是滿腦子那種掛慮、放不下的注意力。那份擔憂後來轉成了「盯著、提防」：留意一件事，好讓它平安無事。
etymonline.com/word/care
Three branches
仔細周密
從「怕出錯」轉到「把每個細節都顧到」。前一家的重點是提防壞事，這一家的重點是把事情做得又細又好——同樣是專注，方向從「防」變成「精」。
thorough, attentive to detail · adjective · A2
Giving a lot of attention to small details so that something is done well and correctly.
仔細 / 周密
用錢謹慎（節儉）
把那份謹慎專門用在花錢上：每一塊錢都盯著，不亂花。核心的「小心」縮到金錢這個範圍，就成了「省」。
thrifty, frugal · adjective · A2
Not spending more money than you need to; good at saving.
節儉
原始詞典資料4 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
carefuladj/ˈkɛɹfəl/
- 1
Taking care; attentive to potential danger, error or harm; cautious.
- He was a slow and careful driver.
- Be very careful (while) trekking through the jungle.
- 2
Conscientious and painstaking; meticulous.
- They made a careful search of the crime scene.
- At the same time, we were cognisant that careful scholars should never solely rely on their own impressionistic observations, and, that our own impressions were inexact and not capable of being quantified.
- 3
obsoleteFull of care or grief; sorrowful, sad.
- 4
obsoleteFull of cares or anxiety; worried, troubled.
- Where through long watch, and late daies weary toile, / She soundly slept, and carefull thoughts did quite assoile.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。