hard before, Tom is afraid of failing in the exam.
A. Having been worked
B. Not to have worked
C. Having never worked
D. Never have worked
网友回答
A. Having been worked
B. Not to have worked
(答案→)C. Having never worked
D. Never have worked
解析：考察非谓语动词.句意:从来没有努力学习过.汤姆担心考试会不及格. 现在分词表示正在进行的伴随性动作,和句子主语是主谓关系. 如果动作发生在谓语动词之前,则要用完成事态的现在分词,结合语境可知选C.