题干

已知两定点F1(﹣1,0),F2(1,0)且|F1F2|是|PF1|与|PF2|的等差中项,则动点P的轨迹方程是____ 

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答案(点此获取答案解析)

x
2
4
+
y
2
3
=1

同类题1

阅读理解

    My transportation was unexpectedly smooth and I arrived at the meeting half an hour earlier. I kept my eyes on the restaurant door. Several customers entered, but not my friend. At 6:00 pm, she sent me a text message:“Urgent work to finish. Will be 20 minutes late.”

I had left my book in the office, so I spent the time thinking of my experiences of being late in China. On my first visit in 1985, punctuality was deeply rooted in the Chinese hearts. There were no traffic jams then.

    As a teacher in Canada, I always insisted on punctuality. I would open the classroom door to a late student for the first time and the second, but not the third. During the six years I worked for CCTV, I had a Chinese friend whom I often saw at lunch time, or after work. We used to meet at the subway station nearby. He was always late by 10-20 minutes. To myquestion, “You were busy?” he would surprisingly answer, “ No.” Once I asked him to check the clock in his office, he smiled.

    In March 2015, I got permanent residence (居住权) in China.The ceremony was scheduled for 9:00 am at the Public Security Bureau on the Second Ring Road. I told my driver I had to get there by 8: 40 am. “No problem,”he replied. But he thought he had time to drop someone off at the airport before picking me up. I desperately waited for him. Then, to rub salt into my wound, he had to stop at the exit of a gas station. Finally, I entered the room at 9:07 am ── the last guest to arrive!

同类题5

阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项。

    After thirty years in the classroom, I have come to realize that teacher's behavior can make a world of difference for a child. This is one such 1.

    While I was attending a party being 2 at a high school one evening, I looked around and noticed a young girl who looked 3. I thought she had been a(n) 4 of mine. I tried to remember her 5, but I couldn't. I felt so frustrated (沮丧的), 6 I have always been able to 7 former students.

    Her eyes met mine and she threw her 8 around me and said, “Mrs. G, it's me, Sarah, and I'm still 9!” The memories 10. You see, Sarah was 11 a student in my classroom. Sarah's mother had abandoned (遗弃) her, and her father had 12 her. She was sent to live with her grandparents the year I 13 her. Sarah was angry, often in 14 and often in the office.

    It was during one of those 15 visits that I first met her. She was writing. I introduced myself to her and asked her 16 she was writing. Sarah shared her story with me. I knew it was healing (康复) for her to put her 17 on paper. Every morning before school she would come into my classroom and we would work on her writing skills.

    Our conversation that evening was filled with 18. She expected to go to college. Driving home, I could not help but 19 the impact (影响) for both good and bad that teachers have upon their students. Taking the time to 20 with a child has the power to change that child's life. That's why I teach.