下列各句中，没有错别字且划线字的注音全部正确的一项是（    ）

已知平面向量 $\overrightarrow{a}$ 、 $\overrightarrow{b}$ 满足| $\overrightarrow{a}$ |=| $\overrightarrow{b}$ |=1， $\overrightarrow{a}$ • $\overrightarrow{b}$ = $\frac{1}{2}$ ，若向量 $\overrightarrow{c}$ 满足| $\overrightarrow{a}$ ﹣ $\overrightarrow{b}$ + $\overrightarrow{c}$ |≤1，则| $\overrightarrow{c}$ |的最大值为（   ）

都江堰、大运河、莫高窟、明长城、北京故宫都是（    ）

2016年12月30日，盐城市区内环高架快速路网二期工程全程全线通车，至此，已通车的内环高架快速路里程达57000米，用科学记数法表示数57000为____．

根据短文理解，完成各题任务。
C
    Sally is an English girl. She is my English teacher, Mrs. Brown's daughter. She is only five years old. (A)She can't go to school. She likes playing ping-pong.
    Her favorite ping-pong player is Zhang Yining. Sally is in the ping-pong club. She goes to the ping-pong club every day. She plays ping-pong for two hours there.
    Sally has a sister. Her name is Maria. She is in our class. She likes running. She runs with her mother every morning. (B)她最喜欢的赛跑明星是刘翔. Maria says she wants to be a running star like Liu Xiang.