问题
选择题
Once______ in the exam, the students who’ve done it would be punished.
A．caught cheated
B．catching cheating
C．being caught cheating
D．caught cheating
答案
答案：D
考查固定结构。Catch sb doing sth抓住某人正在做某事。the students与catch构成被动关系，使用过去分词的形式。结合句意可知D正确。句意：一旦考试作弊的学生被抓住，这些学生会被惩罚。