A：服务业
B：工业
C：农业
Sam: Come on, it's time for school.
Mike: What class do you have today?
Sam: I have math, music and PE. How about you?
Mike: I have English, art and music.
Sam: I like English. What about you?
Mike: I like music.
选择正确的答案填在括号里。
在经纬网中有两条经线和一条纬线是不用标注东西经或者南北纬它们是（ ）
①0°经线 ②0°纬线 ③180°经线 ④20°经线．
人体的血液循环路径分为（ ）
