问题描述：
请问这道题为什么不能选B而选择C呢
The police asked the children _______ cross the street ________ the traffic lights turned green.
A.not; before B.don’t; when C.not to; until D.not; after
The police asked the children _______ cross the street ________ the traffic lights turned green.
A.not; before B.don’t; when C.not to; until D.not; after
问题解答：
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