今天這個講解內容較多，就做成文章+配例句視頻的形式了，省的大家聽一大段囉嗦（視頻在後面）。
apt是大學六級程度的詞彙，算是有一定難度，不過在日常生活中應用頗多。它第一個含義是「恰當的」。如果在英漢詞典裡搜「恰當的」，我們會得到好多個熟悉的詞：
proper ； fit ； appropriate ； suitable ； right……
網上有不少辨析這幾個詞的帖子，通常都說不到點上，因為都是在複述詞典，試圖從釋義裡找差異，而沒有從語感層面去把握。這些詞的確很多時候可以翻譯成「恰當」，但和apt相比，它們更多時候是「適當」。
所謂「適當」，就是不多不少、不偏不倚。
比如說"an appropriate description"和"an apt description"，都可以翻譯成一個「恰當的描述」。但前者的潛臺詞是：這個描述「不偏不倚」，也就是不誇大不貶低，比較公允；後者的潛臺詞是：這個描述「恰如其分」，也就是那種"exactly"的感覺。
後面視頻裡會有兩段apt description的例句，來自《鋼鐵俠2》和《驚天魔盜團》。
當然，有時候這種語感層面的差別界限比較模糊，並不能像詞典裡那樣明確地定義。甚至連母語者也未必總能做出非黑即白的選擇——一個活的語言，魅力也正在於此。有的時候，apt也會做「適當」講——跟suitable、right意思差不多（見視頻：例句3——《星際迷航》）。
apt第二個詞義是易於…的/傾向於……的，或「可能會（經常做某事）的」。常用的形式是be apt to do sth或者be apt to be sth，比如：
The kitchen roof is apt to (= likely to) leak when it rains.下雨時廚房的屋頂容易漏水。She's in her eighties now and apt to be a little forgetful.她現在八十多歲了，容易忘事。
後面視頻裡會有來自《卡薩布蘭卡》和《大地驚雷》的例句。
最後apt還有第三個意思——（形容學生）「聰慧的」。這個用法比較正式老派，視頻裡只舉一個《迷魂記》的例句供參考。
好了，下面是例句視頻合集：
瀏覽器版本過低，暫不支持視頻播放
詞義註解：
apt
adj.1，恰當的a (most) apt description恰如其分的描述2，易於…的/傾向於...的/可能會（經常）（做某事）的be apt to do sthbe apt to be sth3，[正式]（形容學生）聰慧的
例句原文：
恰當的:
Iron Man 2- Well, how would you describe your..? - I would describe it by defining it as what it is, sir.- As? - It's a high-tech prosthesis.- That is, that's actually the most apt description I could make of it.Now You See Me - What exactly is mentalism?- Tricks, mostly. Um, some science.- Targeted guessing might be a most apt description.- Along with some intuition and the occasional...- Voices in my head.
恰當/適當的:
Star Trek Into Darkness - Well, Kirk, it seems apt to return you to your crew.- After all, no ship should go down without her captain.柯克，看來該送你回到你的船員身邊了。畢竟，船長得跟自己的飛船共存亡。
容易/傾向於/有可能：
Casablanca- I recognize you from the news photographs, Monsieur Laszlo.- In a concentration camp, one is apt to lose a little weight.True Grit- We don't need him, do we Marshall?- Gonna miss his Sharps Carbine.- It's apt to get lively out here.
（形容學生）聰慧的：
Vertigo - Then what did he do? Did he train you? Did he rehearse you?- Did he tell you exactly what to do, what to say?- You were a very apt pupil, too, weren't you?- Why did you pick on me? Why me?- Your accident!