zhè / liǎng gè / tuǒ yuán / shì / gòng jiāo / de / tā men / yōng yǒu / xiāng tóng / de / jiāo diǎn

这两个椭圆是共焦的，它们拥有相同的焦点。

These two ellipses are confocal; they share the same foci.