题型：判断题 在B栏中找出与A栏问题相对应的答语，将序号填在括号里。 A ( ) 1. What's the dog doing? ( ) 2. What are they doing? ( ) 3. Can geese swim? ( ) 4. Can I speak to your mom? ( ) 5. What is your mother doing? ( ) 6. Is your father reading a newspaper? B A. Yes, they can. B. It's swinging. C. They are dancing. D. She is washing the clothes. E. Sure. F. Yes, he is. 查看答案
题型：判断题 设A是n阶矩阵，则下列说法错误的是 ( )．A．对任意的n维列向量ξ，有Aξ=0，则A=0．B．对任意的n维列向量ξ，有ξTAξ=0，则A=0．C．对任意的n阶矩阵B，有AB=0，则A=0．D．对任意的n阶矩阵B，有BTAB=0则A=0． 查看答案