题目

Though I have often heard this song _______. I have never heard you _______ it. A. being sung, sang          B. sang, singing C. sung, sing                D. to be sung, to sing   答案：C第一空填 sung，因为 song 与 sing 是被动关系；第二空填 sing，因为 you 与 sing 是主动关系。 Mary isn't here at the moment. She  _______ later.     A. comes         B. came             C. has come         D. is coming