—Howdidyouknowthedetailsofthatsurprisingnews?—Ihappened...

問題詳情：

—How did you know the details of that surprising news?

—I happened _________ the event then.

A. to be listening     B. to have covered   

C. to be covering     D. to have listened

【回答】

c

知識點：不定式

題型：選擇題