You can picture a teacher standing just behind whatever is in front of you. The poem, the film, the museum sign, the person talking to you: each one has someone behind it who wants you to come away having learned something. Didactic names that teacher standing there, and much of the time the complaint is simply that you can see them too clearly.
可以想成：你看的東西後面站著一位老師。那首詩、那部電影、那塊解說牌、跟你講話的那個人，背後都有一個「想教會你什麼」的人。didactic 就是在指那位站在後面的老師。很多時候抱怨的點不是他教錯了，而是你太看得見他。課程分類的用法則不一樣：那裡只是把「用教的那一塊」跟「動手做的那一塊」分開，沒有誰站得太前面的問題。
From the word’s history
The word came into English through French didactique, from Ancient Greek didaktikos, skilled in teaching, built on didasko, to teach. The teaching is in the word itself, not added later.
這個字經法文 didactique 進入英文，來自古希臘文 didaktikós「擅長教學的」，字根是 didáskō「教」。「教」從一開始就在字裡，不是後來才加上去的。
Wiktionary, "didactic"
登入就可以看每一支怎麼連回核心畫面。