A. It's time for Chinese class.   B. It's time for lunch.

C. It's time for school.          D. Time to go home.

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设集合M和N为平面中的两个点集，若存在点$A_0\in M,,B_0\in N$，使得对任意的点$A\in M,,B\in N$，均有$\left|AB\right|\ge \left|A_0{B}_0\right|$，则称$\left|A_0{B}_0\right|$为点集M和N 的距离，记为$d(M,,N)=\left|A_0{B}_0\right|$.已知集合$M=\left\{\left(x,y\right)|x^2+{\left(y-2\right)}^2\le 1\right\}$ ,$N=\left\{\left(x,y\right)|\left\{\begin{array}{c}x-y\ge 1\\ x+y\le 4\\ y\ge 1\end{array}\begin{array}{c}\\ \end{array}\right.\right\}$，则d(M,N)=（   ）

To be honest, I'd rather stay at home than go out with him.  

不属于地图基本要素的是（    ）