题目

Nick was not the kind of boy I had expected to spend my summer with. I was hoping to     have a   21   the summer before my busy senior year, but my mother asked me to do her a   22  . One of her colleagues needed a full-time   23  . “You planned to volunteer at the local hospital, why not volunteer to   24   Nick instead?” Then she told me that this six-year-old boy was not a   25   child. Nick was a lovely little boy who suffered from many disorders. Normal day-care centres would not   26   him. As a baby, he had serious ear infections which left him wit将珍珠加入稀盐酸中有气泡产生，生成的气体能使澄清的石灰水变浑浊，则珍珠中含有下列离子中的 [　　] A．氯离子 B．硫酸根离子 C．碳酸根离子 D．氢氧根离子