一个5阶矩阵A的列向量组线性无关,则A的秩为 ____
What was Lisa's main task as a volunteer?
A. To clean the toliets in a hospital.
B. To teach in a local school.
C. To build toilets and help in an eye hospital.
D. To work as a cleaner in a school.
How long did the experience in the eye hospital last?
A. Eight hours.
B. Two days.
C. One week.
D. Two weeks.
How did Lisa compare the experience with travelling?
A. She preferred travelling.
B. She found it harder.
C. She didn't notice the difference.
D. She found it easier.
微信支付 
支付宝支付