第29题: [单项选择]Only recently ______ to realize the dangers caffeine might bring to our health. A. that scientists began B. have scientists begun C. scientists have begun D. that did scientists begin 参考答案:B 答案解析:[考点] 倒装
[句意] 直到最近科学家才意识到咖啡因可能会危害我们的健康。
[解析] only+状语位于句首时,句子要求部分倒装。选项[D]中多了一个that,而且时态采用一般过去时也不是很准确