人体口腔上皮细胞(以圆圈代表)转移至不同浓度(Ⅰ、Ⅱ、Ⅲ)的三种盐溶液中，结果如右图所示。这三种溶液的浓度是（    ）

    It is Saturday morning. Mrs. Black and her daughter Kate go to the bookshop near their house. Mrs. Black wants to buy some picture books for her grandson. Kate wants to buy some storybooks. In the bookshop Kate meets her old classmate, Sue. They are good friends. They talk and talk for a long time and forge to buy books. At twelve o'clock Mrs. Black finds them and asks Sue to go and have lunch in their house, Sue says: “Yes.” The two girls are very happy.