第 16 至 20 題為題組        People may express their feelings differently on different occasions. Cultures sometimes vary greatlyin this regard. A group of researchers in Japan, __16__ , studied the facial reactions of students to a horrorfilm. When the Japanese students watched the film __17__ the teacher present, their faces showed onlythe slightest hints of reaction. But when they thought they were alone (though they __18__ by a secretcamera), 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 thestudents masked their upset with a poker face in the experiment.
【題組】16.
(A) as usual
(B) in some cases
(C) to be frank
(D) for example