单选题 Though the horses got off with a good start, it was not long______ most of them were out of the race.
A. before B. after C. when D. until

【正确答案】 A

【答案解析】[解析] 本题考查句型It is/was not long before...(没过多久就……)的用法。所以从意思和句子的结构上来看，选项A是正确答案。
[译文] 虽然那些马一开始跑得很好，但没过多久，大部分的马就没有希望赢了，