沒把它掛在心上
care 的另一半是「在乎、掛心」。少掉的如果是這一份，畫面就從「手忙腳亂」換成「聳聳肩」：事情擺在眼前，人卻沒把它放進心裡。
unconcerned · adjective · B1
not worried about something; treating it as if it is not important.
不在意的；不關心的
核心畫面
The word is care with -less written on the end: the care is simply not there. Picture someone carrying a full cup while looking at their phone — the attention that should be on the cup has gone somewhere else, so tea ends up on the floor. That missing attention can be held as the picture inside 'careless'. English uses care for two things, though: the attention you put into doing something, and the concern you feel about something. Take either one away and the word still fits — which is why careless can mean sloppy, and can also mean untroubled.
這個字就是 care 後面掛上 -less：那份 care 不在了。可以想成一個人端著滿滿一杯茶，眼睛卻盯著手機——…更多收起
這個字就是 care 後面掛上 -less：那份 care 不在了。可以想成一個人端著滿滿一杯茶，眼睛卻盯著手機——本該放在杯子上的注意力跑掉了，於是茶灑了一地。careless 的畫面比較像這個「少掉的那一份」。而英文的 care 同時涵蓋兩件事：做事時投進去的注意力，以及心裡對某事的掛念。少掉哪一種，這個字都成立——所以 careless 可以是「粗心」，也可以是「不放在心上」。From the picture
Also in this word
inattentive · adjective · B1
not giving enough attention to what you are doing, so you make mistakes or cause problems.
粗心的；不小心的
casual, unstudied · adjective · B1
natural and easy, done without trying hard or planning how you look.
隨意的；自然不做作的
原始詞典資料3 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。
carelessadj/ˈkɛəlɪs/
- 1
Not concerned or worried (about).
- "He was here," observed Drina composedly, "and father was angry with him." "What?" exclaimed Eileen. "When?" "This morning, before father went downtown." Both Selwyn and Lansing cut in coolly, dismissing the matter with a careless word or two; and coffee was served—cambric tea in Drina's case.
- 2
Not giving sufficient attention or thought, especially concerning the avoidance of harm or mistakes.
- Jessica was so careless that she put her shorts on backwards.
- These ballads, none of which are later than the fifteenth century, are written in a strain of the most artless simplicity, not the slightest attempt at ornament is to be discerned in them; the same ideas and expressions continually recur, and the rimes are the most careless imaginable, often a mere assonnance in vowels or consonants, sometimes not possessing even that slight similarity of sound.
- 3
archaicFree from care; unworried, without anxiety.
- Jessica was careless about putting her shorts on properly.
- Good-humored, easy, and careless, he presided over his whale-boat as if the most deadly encounter were but a dinner, and his crew all invited guests.
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。