IwastoldtomeetMr.Greenattheairport.ButIdon’tknow

問題詳情：

I was told to meet Mr. Green at the airport. But I don’t know ______ he will arrive.

  A. where                    B. why                    C. how                       D. when

【回答】

D

知識點：連詞

題型：選擇題