英语周报第12期20182022答案

8.D【解析】本题考查抛物线的简单几何性质、直线与圆的位置关系.抛物线C:y2=4x的焦点F(1,0),准线方程为x1,过点M作MD与准线垂直并交准线于点D.令直线l为直D线x (m-1)y=5-2m,变形可得m(y 2)ry 2=0解得5=0直线l经过定点(3,-2).设P(3,-2),连接FP,取FP的中点为E,则E的坐标为(2,-1),EP=2.若FN⊥l,则N在以FP为直径的圆上,以FP为直径的圆的方程为(x-2)2 (y 1)2=2.又由MF|=|MD|,得|MF| |MN|=|MD1 |MNI,如图,MD MN的最小值为圆(x-2)2 (y 1)2=2上的点到准线的距离的最小值,过点E作ED′与准线x=-1垂直并交于点D,与圆E交于点N,与抛物线交于点M,则D'N即为MD| |MN的最小值,即{|MF! MN1)mn=|DN|=|ED|-r=3故选D.

第二节this time, Lewis was so distracted by the UFO.That's when the object entered the last cloud. From thereit was nothing but open sky. "When it appeared, my lifechanged, "Lewis says. "There against the richness of theblue sky was a silvery shape that seemed to have arms andlegs! It was so beautiful to look at. At the same time, ithad the appearance of metal. It looked like some kind ofship with a strange design. The best way I could describe itis that it looked like a silver tool in the design of thestickman children draw. It was huge, moving fasst anmade no noise.As it sailed overhead, some of the arms and legsould move up and down, giving the impression of beingalive!"He says. "It made a couple of rolls, reflecting thesun in every direction just beautiful! Slowly it landed onthe land. I imagined extraterrestrials would come out, butthat didn't happen. Then it began to rise and move fartherand farther away. As it started to fade away from myview, I found myself short of breath and with tearsrunning down my cheeks. It had that much of an effect onme. I began thinking maybe that's what an angel lookslike

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