如图所示的各电场中，a、b两点的电场强度相同的图是（   ）

    Mildred Webinga Freeman was an English teacher at the new middle school I attended in the ninth grade.She wasn't my1;she was the adviser to the safety patrol（巡逻）on which I2.I loved being around her and3her sense of humor and kind personality.She was4a good listener.

    At the end of the year,she5that she was moving to Florida,and I was very sad.We exchanged6and became pen pals.I could tell her7,and she treated me8respect even though I was a teenager.

    In Florida ,Mrs. Freeman became a Realtor（房地产经纪人）,9she managed to find time to write letters.She wrote10stories and always took my concerns11.She had given me a(n)12invitation to visit,and I missed her so much.When I13to take her up on the14,she answered,"Get your shoes on and your bags15!You are welcome anytime!"

    I spent three weeks with her in Miami.Her16of poetry,music,and creative writing17me to follow these endeavors（努力）.One day18hanging sheets on the clothesline,she19and said,"You know,the sky is fuel for the soul."I had never looked at the20before hearing those words.Later that year,I received a call that Mrs.Freeman had died.

大豆是我国一种重要的经济作物，下图甲至丙分别是大豆种子、大豆幼苗和大豆的豆荚．请结合所学生物学知识回答下列问题：

2013年12月2日嫦娥三号发射升空，12月14日嫦娥三号探测器在月球表面成功软着陆，下列说法正确的是（　　）