【单选题】下列所有情况均符合肺出血肾炎综合征,哪项除外?( )
【单选题】I wish I could be ________so that I could be able to sneak around and see things I would not normally be able to see.
【简答题】矩阵A,B能够相加必修具备什么条件? 矩阵A,B能够相乘必修具备什么条件? 举例说明矩阵乘法不满足消去律。
【判断题】Sometimes I wish I be living in a different time and a different place.
【简答题】I wish I (be) a bird.
【判断题】这里可以得到X_{12}是零矩阵,所以矩阵的乘法满足消去律。