The study also shows that there are several unspoken rules about how feelings should be 19 shown on different occasions.
答案：(C) properly
properly shown（適當地表現出來）符合「關於情緒該如何『恰當地』在不同場合表現，有一些不成文規定」的語意。rarely（很少）、similarly（同樣地）、critically（批判性地／危急地）都不符合這裡「恰當表現情緒」的語意。
四個選項都是 -ly 結尾的副詞，形態一模一樣，你會挑一個讀起來最順的。
四個選項都是副詞、都放得進 be 動詞與過去分詞之間，形態這條路整個斷掉，可見這一格考的是語意。先看整句在講什麼：there are several unspoken rules about how feelings should be ______ shown on different occasions（有幾條不成文的規定，規範在不同場合情緒該______表現出來）。既然是「規定」，講的就是「該用什麼樣的方式表現才恰當」，所以空格要的是一個評價方式合不合宜的字，也就是 properly（適當地、恰當地）。下一句 One of the most common rules is minimizing the show of emotion（最常見的一條規定是把情緒的流露降到最低）正是在舉一個「怎樣才算恰當」的例子，可以拿來驗算。
rarely（很少、難得）是頻率副詞，講的是次數不是方式，而且不成文規定不會要求情緒「很少被表現」這種次數上的規範；similarly（同樣地）需要前面先有一個拿來對照的東西；critically 有「批判地」與「嚴重地」兩個意思，擺在這裡兩個都接不上「情緒怎麼表現」。
properly（適當地、恰當地）、unspoken rules（不成文的規定）、on different occasions（在不同的場合）、minimize（把……減到最低）、rarely（很少、難得）、critically（批判地；嚴重地）。
People may express their feelings differently on different occasions. Cultures sometimes vary greatly in this regard.
A group of researchers in Japan, 16, studied the facial reactions of students to a horror film. When the Japanese students watched the film 17 the teacher present, their faces showed only the slightest hints of reaction. But when they thought they were alone (though they 18 by a secret camera), their faces twisted into vivid mixes of anguished distress, fear, and disgust.
The study also shows that there are several unspoken rules about how feelings should be 19 shown on different occasions. One of the most common rules is minimizing the show of emotion. This is the Japanese norm for feelings of distress 20 someone in authority, which explains why the students masked their upset with a poker face in the experiment.