A：唐朝的三省六部制
B：周朝的分封制
C：秦朝的郡县制
D：元朝的行省制度
— My cousin is good at all his subjects at school, but he never ________.
— What a ________ boy! We should learn from him.
修改病句。
小明的学习成绩好的原因是他认真学习的结果。
四七二十八
计算．
18→+8□→−20□
27→−4□→+15□
My watch is broken. It _____.
