The largest, most systematic program of ethnic extermination was the murder of 11 million people--close to six million of whom were Jews--by the Nazis before and during World War Ⅱ.

【参考答案】

最大规模的和最有系统的种族灭绝行为是二战前和二战进行过程中纳粹分子对1100万人的大屠杀计划，其中600万人是犹太人。