求解线性方程组的高斯主元消去法的条件为()。
A.三对角矩阵
B.上三角矩阵
C.对称正定矩阵
D.各类大型稀疏矩阵
参考答案：D
Tibet is facing a (an)________ task to maintain stability and all government workers must be on their
highest guard ahead of the Tibetan New York. [ ]
A. concerned
B. subtle
C. ridiculous
D. urgent
激励的方法有环境气氛激励、目标理想激励、榜样激励、荣誉激励、感情激励和奖励激励。
