— Do you often visit your grandparents?
— Mmm… , I’m afraid. I usually phone them.
A. over again
B. time and again
C. once again
D. now and again
网友回答
A. over again
B. time and again
C. once again
(答案→)D. now and again
解析：over again反复，time and again和over again 均为又一次之意。now and again时而，只有D与题意相符。