257＋299=____

1940－1762=____

完形填空

   Nancy is reading an e-mail from her friend Jack. She is very1 to get the e-mail. Jack writes about his school2 his weekends. Jack likes his school very much. Nancy likes her school,3 . Jack's school is very big and he likes his classroom. The4  and chairs are new. There are lots of pictures5 the wall. They clean the classroom every day.

   Jack doesn't 6to school at the weekend. He gets up7at six on Saturday. He exercises in the park for half8. Then he eats his breakfast. He helps his mother do the9. At eight he begins to do his homework. He has lunch in a fast food restaurant (快餐店). In the10, he goes shopping with his mum. Sometimes he plays computer games or chats with his friends on the Internet. He enjoys his weekends very much.

已知：烷基苯在高锰酸钾的作用下，侧链被氧化成羧基：

$\stackrel{MnO\left(H\right)}{\to }$

$\stackrel{Fe/HCl}{\to }$ （苯胺，易被氧化）

请根据本题所给信息与所学知识回答下列问题：