It has been announced that it won’t be long _________ our country _________ an unmanned spaceship to explore the moon．A.before; sends upB.until; sends upC.since; sends upD.before; will sends up
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A解析句意：据宣布，不久，我国就会发射非载人宇宙飞船去探测月球。题干是一个It won’t be long before＾句式。before引导的时间状语从句要用一般时代替将来时。