下列关于物质用途的说法中，错误的是（　　）

②滴入氢氧化钠溶液，三支试管中均没有出现预料中的蓝色絮状沉淀：小刚的试管中是黑色浑浊；小强向试管中是蓝色溶液；小柯的试管中虽然出现过少量蓝色沉淀但又马上变成了黑色沉淀．于是三位同学开始探究实验失败的原因，经过一番讨论和观察他们认为与反应物的量和条件有关：

    There is a woman ____（name）Daisy who has devoted all her life to ____（attend）to the homeless children. It's generally recognized that what she has done for children ____（deserve）to be respected by everyone. ____（personal）speaking, her selfless behavior sets a good example to us.

    There was a time when I came across Daisy who ____（invite）to deliver a speech, during which she indicated, “____（take）care of homeless children is just ____ ordinary job, but it doesn't mean that you can look down ____it. Every job is equal. We can't say which one is ____（good ）.” She also said, “Once you set out to do something, you ought to carry on with it to the end, ____ you will gain nothing in the end.”

大珠江三角洲城市群的核心城市是（   ）