代数式x²+2x+7的值是6，则代数式4x²+8x-5的值是(  )

已知矩阵$\left(\begin{array}{cc}\sin \alpha +\cos \alpha & 0\\ \sin \beta +\cos \beta & 1\end{array}\right)$为单位向量，且α，β∈$\frac{\mathrm{\pi }}{2}$，π），sin（α﹣β）的值____ ．

四个完全一样的 可以拼成一个____。

Peter: Let's play computer games!
Barry: That sounds interesting, but I don't have a computer.
Peter: Well, do you have a volleyball?
Barry: Yes.
Peter: Then let's play volleyball.
Barry: Oh, volleyball is so difficult.
Peter: OK, let's watch TV.
Barry: That sounds boring. Hmmm, let's play soccer! Do you have a soccer ball?
Peter: No, I don't.
Barry: Oh, well, do you have a basketball?
Peter: Yes, I do. Let's play basketball!
Barry: That sounds fun!