Only after Mary read her position the second time the spelling mistake.(2012·天津)
A. did she notice
B. she noticed
C. does she notice
D. she has noticed
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(答案→)A. did she notice
B. she noticed
C. does she notice
D. she has noticed
解析：考查倒装和时态。句意：只有玛丽把作文读了第二遍之后，她才注意到拼写错误。当only＋状语位于句首时，主句要部分倒装。因此可先排除B和D。由句中的“Mary read”可知，动作发生在过去，因此选did she notice。