The US is the fourth largest country in the world. It's smaller than Russia and China. Washington DC is its capital. But it is a quiet city.New York is the biggest city in America and it's one of the biggest cities in the world. It is the east of the US and at the south of the Hudson River(哈德逊河).A large part of the city is on Manhattan Island(曼哈顿岛), a big island in the river. New York has a larger population(人口) than Washington DC. In New York, we can see a famous statue, the Statue of Liberty(自由女神像)

⑴⑵⑶根据短文内容，选择正确的单词或短语把句子补充完整；⑷⑸根据短文内容，选择正确答案。

某班体育委员对本班学生一周锻炼时间（单位：小时）进行了统计，绘制了如图所示的折线统计图，则该班这些学生一周锻炼时间的中位数是____小时．