第8题: [单项选择]The basic causes are unknown, although certain conditions that may lead to cancer have been ______. A. identified B. guaranteed C. notified D. conveyed 参考答案:A 答案解析:identify意为:识别,认出;guarantee保证,使确信;notify通知,告知;convey传递,传达(信息或消息等)。句意:致癌的根本原因还不清楚,可是已经发现某些导致癌症的情况。