若a²-b-1=0，则代数式-2a²+2b+8的值为（    ）

两颗靠得很近而与其它天体相距很远的天体称为双星，它们以两者连线上的某点为圆心做匀速圆周运动，如果二者质量不相等，则下列说法正确的是（   ）

In England ,people don't often talk to each other when they travel. If you get on a bus or a train. you can see people sitting and looking out of the window. Other people may read books or newspapers.
When you meet English people, they often start a conversation by talking about the weather . So when you meet somebody in England, you can say, "Nice weather for the time of the year!"
"But it was a little cold yesterday, "somebody may answer.
"But it will get a bit warmer later,"you can say.
Talking like this, they will think,"How friendly you are!"

定义在R上的函数f(x)满足$f\left(x\right)=\left\{\begin{array}{c}{x}^2,x\in 0,1)\\ x,x\in -1,0)\end{array}\right.$且$f(x+2)=f\left(x\right)$，$g\left(x\right)=\frac{1}{x-2}$，则方程$f\left(x\right)=g\left(x\right)$在区间$-3,7$上的所有实根之和最接近下列哪个数（   ）