若对n个向量 a 1 ? a 2 ,… a n 存在n个不的实数k 1 ,k 2 ,…,k n ,使得k 1 a 1 +k 2 a 2 +…,k n a n =成立,则称向量 a 1 、 a 2 ,… a n 为“线性相关”.依此规定,能说明 a 1 =(1,2), a 2 =(1,-1), a 3 =(2,2)“线性相关”的实数k 1 ,k 2 ,k 3 依次可以取 ______(写出一组数值即中,不必考虑所有情况).
【单选题】In the sentence 'Others, most African Americans, were involuntarily transported to North America to do forced labor or to be sold as slaves.', the word 'involuntarily' can be explained as ______.