根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    Xiao Lin has a good friend. Her 1 is Lucy. She is from the USA. She's a(n) 2. Xiao Lin and Lucy  3 in the same class. They go to school five days a4. They stay at  5 on Saturday and Sunday. Lucy 6 China and Chinese food. Her favorite  7 is rice cake. At school they play football after class. Xiao Lin and Lucy like 8 things. Now they are making a plane. They like flying planes on Saturday and Sunday. Lucy 9 English and a little Chinese. They are  10 friends.

某校九年级（1）班所有学生参加2010年初中毕业生升学体育测试，根据测试评分标准，将他们的成绩进行统计后分为A、B、C、D四等，并绘制成如图所示的条形统计图和扇形统计图（未完成），请结合图中所给信息解答下列问题：

（1）九年级（1）班参加体育测试的学生有____ 人；

（2）将条形统计图补充完整____ ；

（3）在扇形统计图中，等级B部分所占的百分比是____ ，等级C对应的圆心角的度数为____ ；

（4）若该校九年级学生共有850人参加体育测试，估计达到A级和B级的学生共有____ 人．

    I'm Sally.I have three new teachers.A Chinese teacher，a maths teacher， and an art teacher.My Chinese teacher is Miss Zhang.She's pretty and young.My maths teacher is Mrs Liu.She's tall and thin.My art teacher is Mr Sun.He's tall and strong.He's very kind.

能证明锌、铜、银的金属活动性顺序的一组试剂是                      （ ）
①铜、银、硝酸锌溶液；②锌、银、硝酸铜溶液；③锌、铜、稀硫酸、硝酸银溶液；④锌、铜、稀硫酸。