Though iPhone 4 is such a hit product, I won’t buy one unless its after service .
A. was improved
B. gets improved
C. is improving
D. had got improved
网友回答
A. was improved
(答案→)B. gets improved
C. is improving
D. had got improved
解析：主句I won’t buy one用的是一般将来时态，所以unless引导的条件状从要用一般现在时表将来；且its after service和improve的动宾关系，所以用一般现在时态的被动语态。选B。