We all know that __________ is the first requirement for learnin

We all know that __________ is the first requirement for learning, （concentrate）
【正确答案】：concentration
【题目解析】：分析句子成份可知that引导的宾语从句中缺少主语，动词不能做主语，而名词可做主语，concentrate意为”集中“，是动词，其名词形式为concerntration集中，专心。