Though iPhone 4 is such a hit product, I won’t buy one unless its after service ______.A.was improvedB.gets improvedC.is improvingD.had got improved
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B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。