题干

点A,B的坐标分别为(﹣2,3)和(1,3),抛物线y=ax2+bx+c(a<0)的顶点在线段AB上运动时,形状保持不变,且与x轴交于C,D两点(C在D的左侧),给出下列结论:①c<3;②当x<﹣3时,y随x的增大而增大;③若点D的横坐标最大值为5,则点C的横坐标最小值为﹣5;④当四边形ACDB为平行四边形时, a=-
4
3
.其中正确的是(  )

A:②④

B:②③

C:①③④

D:①②④

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A

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    Horatio Spafford, who was born in 1828, was a wealthy Chicago lawyer with a promising career, a beautiful home, a wife, four daughters and a son.

    At the very height of his financial and professional success Horatio and his wife, Anna, suffered the loss of their young son. Shortly thereafter, on October 8, 1871, the Great Chicago Fire destroyed most of his real estate(地产) Investment.

    In 1873, Spafford planned a boat trip to Europe in order to give his wife and daughters a much-needed vacation and time to recover from the loss of their young son. Spafford sent his wife and daughters ahead of him while he remained in Chicago to take care of some small business. Several days later he received notice that his family's ship had had a collision (碰撞). All four of his daughters had drowned, only his wife had survived.

    With a heavy heart, Spafford boarded a boat that would take him to his broken-hearted Anna in England. It was on this trip that he wrote those now famous words: When sorrows like sea billows roll, it is well, it is well with my soul.

    Philip Bliss (1838-1876), composer of many songs, including Hold the Fort, Let the Lower Lights be Buming, and Jesus Loves Even Me, was so impressed with Spafford's life and the words of his hymn (赞美) that be composed a beautiful piece of music to accompany the poem. The song was published by Bliss and Sankey in 1876.

    For more than a century, the tragic story of one man has given hope to countless people.