世界上最早实施义务教育的国家是（ ）。

(单选题)20.（ ） (单选题)19.（ ） (单选题)18.（ ） (单选题)17.（ ） (单选题)16.（ ） (单选题)—Aren’t you Mary’s sister?—______. I’m her aunt. (单选题)She asked me ______ he could dance or sing. (单选题)—Do you want to ______ at the meeting?—No, I have nothing to (单选题)______ Yellow River is the second longest river in our count (单选题)My little sister is so tired, and she can hardly walk, _____