【单选题】
Jogging makes the heart stronger and helps people lose_________.
【单选题】
I want to mail this letter to the U.S.._________ is the postage, please?
【单选题】
I asked some policemen to tell me the way home. They smiled and answered me_________ .
【单选题】
You can increase your_________ a quarter or half mile every two weeks or so.
【单选题】
Professor White is out of office right now. Can you leave a_________ or call later?
【判断题】
设b,a1,a2线性相关,b,a2,a3线性无关,则a1,a2,a3线性无关。
【判断题】
若n阶矩阵A的行列式 |A|不等于0,则矩阵A可逆。
【判断题】
对任意两个事件A和B,有P(A-B)=P(A)-P(B).
【判断题】
行列式两行或两列元素位置对调以后,行列式的值与原行列式的值相差一个负号。