俄罗斯地跨两大洲，这两大洲是    (    )

    Mrs. Green lives in the country, and she doesn't know London very well. One day, she went to London. She couldn't find her1Just then, she2a man near the bus stop. " I can ask him the way." she says to3and asked, "Excuse me, will you please4me the way to King Street?" The man smiled with5answers. He 6know English. He spoke Russian. He was a 7Then he8his hand into his pocket,9a piece of paper and let her10it. On the paper are these words, "Sorry, I don't speak English."

下列固体中属于晶体的是（　　）

已知圆C₁：x²+y²=1与圆C₂：（x﹣1）²+（y+1）²=1交于A，B两点，则直线AB的方程为____