Added to something that already exists, in order to make it more complete or better. The main thing is still there — the supplementary thing comes on top of it. "supplementary materials", "a supplementary payment", "supplementary information".

Added to something that already exists加在已經存在的東西上, in order to make it more complete or better為了讓它更完整或更好。 The main thing is still there原本的主體還在 — the supplementary thing comes on top of itsupplementary的東西是疊加在上面的。 'supplementary materials'「supplementary materials補充教材」, 'a supplementary payment'「a supplementary payment補充給付」, 'supplementary information'「supplementary information補充資訊」。

It is a formal word, at home in schools, offices, government forms and academic writing. In everyday talk people just say extra or additional.

It is a formal word這是一個正式的字, at home in schools, offices, government forms and academic writing常出現在學校、辦公室、政府表格和學術寫作裡。 In everyday talk people just say extra or additional日常說話大家就直接說extra或additional。

But there is a shade of difference worth hearing: extra means simply "more", while supplementary means "more, and it fills a gap in the main thing". A supplementary lesson is not just another lesson — it covers what the main lessons did not.

But there is a shade of difference worth hearing但這裡有個值得注意的細微差別: extra means simply 'more'extra單純表示「更多」, while supplementary means 'more, and it fills a gap in the main thing'而supplementary表示「更多,而且是補上主體裡不足的部分」。 A supplementary lesson is not just another lessona supplementary lesson一堂補充課,不只是「再一堂課」而已 — it covers what the main lessons did not它上的是原本課程沒教到的部分。

A few places you will meet it often: supplementary reading (books beyond the textbook), a supplementary question (a follow-up question after the first answer, common in parliament and interviews), supplementary benefits or supplementary income (money added to what you already earn), and supplementary exams in some school systems (a second chance exam).

A few places you will meet it often有幾個地方你會常遇到它: supplementary reading (books beyond the textbook)supplementary reading補充閱讀(課本以外的書), a supplementary question (a follow-up question after the first answer, common in parliament and interviews)a supplementary question補充提問(第一個答案之後的追問,國會和訪談裡很常見), supplementary benefits or supplementary income (money added to what you already earn)supplementary benefits或supplementary income補充津貼或補充收入(加在你原本收入上的錢), and supplementary exams in some school systems (a second chance exam)還有一些學制裡的supplementary exams補考(給你第二次機會的考試)。

It can also be a noun in British use, meaning a supplementary question, but a learner rarely needs that.

It can also be a noun in British use在英式用法裡它也可以當名詞, meaning a supplementary question指補充提問, but a learner rarely needs that不過學習者很少需要用到這個用法。

American writing often prefers supplemental with almost the same meaning; British writing prefers supplementary. Do not spend energy on the difference.

American writing often prefers supplemental with almost the same meaning美式寫作比較常用supplemental,意思幾乎一樣; British writing prefers supplementary英式寫作比較常用supplementary。 Do not spend energy on the difference不用花力氣去糾結這個差別。