We were soon bored as we had to listen to the______details of his operation.
A、tentative
B、tenacious
C、tedious
D、tenuous
【正确答案】：C
【名师解析】:该题目要求填入合适的形容词来完成句子。根据句子的语境，"we had to listen to the______details of his operation" 暗示了细节是令人厌烦的。选项中，"tedious"（C选项）意为"乏味的"或"令人厌烦的"，符合句子的语境。其他选项："tentative"（A选项）意味着"试探性的"，"tenacious"（B选项）意味着"坚韧的"，"tenuous"（D选项）意味着"纤细的"或"薄弱的"，都不符合句子所要表达的意思。因此，正确答案是C。
