A:《浅议我国早期国家政治制度的创立者—大禹》
B:《趣谈周武王与分封制》
C:《论隋唐三省制度对中国历史的影响》
D:《论清代丞相与军机大臣的权力制衡》
— Can you believe _________ little children can finish the difficult problem in _________ a short time?
— I can't believe it until I see it with my own eyes.