My little son used to drink a lot of fruit juice but these days he mineral water．
A. prefers
B. is preferring
C. preferred
D. had preferred
网友回答
(答案→)A. prefers
B. is preferring
C. preferred
D. had preferred
解析：考查时态。根据句意可知这是一个过去与现在的对比。后面的these days说明本题应该使用现在时表示目前的情况。