第28题: [单项选择]Not until the 1980s ______ in Beijing start to find ways to preserve historic buildings from destruction. A. some concerned citizens B. some concerning citizens C. did some concerning citizens D. did some concerned citizens 参考答案:D 答案解析:句意:直到 20 世纪肋年代,北京一些相关人士开始探索保护历史建筑的方法。本句子用 not until 开头,因此要用倒装句式,A、B 两项缺乏谓语动词。concerned 形容词,表示“关心的,相关