Since Tom ______ downloaded a virus into his computer, he can not open the file now

A.readily

B.horribly

C.accidentally

D.irregularly

答案及解析： C

副词词义辨析。解析：根据句意，只有C项符合题意。由于汤姆无意中下载了病毒到电脑中，现在无法打开这个文件。readily乐意地；horribly可怕地；accidentally无意地，意外地；irregularly无规则地。