Peng'ou Middl School, _______ school in Longhu, held _______ 32nd Shantou Adolescents Science &.Technology Innovation Contest in November, 2016.
A：a; a
B：a; the
C：the; a
D：the; the
(7850－5450)÷(670－622)=____
北宋前期，四川地区出现了____，这是世界上最早的纸币。
