单选题 Scientists estimate that about 530,000 other objects, too small to detect with radar, ______ the Earth too.
【正确答案】 B
【答案解析】[解析] 分析句子结构可知，that引导的宾语从句中缺少谓语，再根据句意判断本题语态应该采用主动语态。故选B。