题目

The early winter storm was much worse than the forecast. In the 1950s,   31   was frequently a best-guess science. “Sweetheart,” Dad said to Mom, “I’ve got to   32   bed and check on the turkeys (火鸡).” When Dad left the house, Mom   33   that he would not be able to make it to the farm,   34   the snow was hitting the little white wooden house at 40 miles per hour. At 7 a. m., Mom was ready to call for   35   when Dad’s truck came into the driveway. Dad, back home   36   outside, nearly fell down on the kitchen floor. “  37   Priest (牧师)已知定点F（1，0），动点P（异于原点）在y轴上运动，连接FP，过点P作PM交x轴于点M，并延长MP到点N，且PM•PF=0，|PN|=|PM|．（1）求动点N的轨迹C的方程；（2）若直线l与动点N的轨迹交于A、B两点，若OA•OB=-4且46≤|AB|≤430，求直线l的斜率k的取值范围．