Britain's smallest school was closed down because its only pupil failed to turn up for class, a famous Britain newspaper reported in May.
The newspaper said the six-year-old girl's parents were unhappy with a teacher who just got the new job to teach the only pupil.
The school had been closed for the last nine months after its former（前任的）teacher retired and the only other pupil moved on to a secondary（中等的）school. The new teacher, Ms. Puckey was to start teaching the girl and reopen（再次打开）the school.
But the girl's mother is keeping her daughter at home.
    “I was not pleased with the new teacher,”the mother said. “I had told the old teacher as far back as last September that if Ms. Puckey got the job, my child would not be going to school.”
    The school lies on an island off the northeast of Scotland. Although there was only one pupil, the school is very good in many ways and has a headmaster, three computers, a television, and an art room as well as a school house with three bedrooms.

已知下列氧化剂均能氧化+4价的硫元素，为了除去稀硫酸中混有的亚硫酸，应选用的最合理的氧化剂是（　　）

工业生产果汁时，常常利用果胶酶破除果肉细胞壁以提高出果汁率．为研究温度对果胶酶活性的影响，某学生设计了如下实验：

①将果胶酶与苹果泥分装于不同试管，在10℃水浴中恒温处理10min（如图A）．

②将步骤①处理后的果胶酶和苹果泥混合，再次在10℃水浴申匣温处理10min（如图B）．

③将步骤②处理后的混合物过滤，收集滤液，测量果汁量（如图C）．

④在不同温度条件下重复以上实验步骤，并记录果汁量，结果如下表：

根据上述实验，请分析并回答下列问题：