我喜欢人多热闹的场合。
A．是
B．否
参考答案：A
You should if you have a fever. [ ]
A. lie down and rest
B. drink tea with sugar
C. drink lots of water
D. see a dentist
1.设A为m×n阶矩阵，证明：r(ATA)=r(A)；
