D., Tang power had ebbed.Domestic economic instability and military defeat in 751 by Arabs, marked the beginning of five centuries of steady military decline for the Chinese empire.

• 唐朝通过科举制度在全国选出优秀的儒家文人为政府效力，而唐朝的政府体系在儒学官僚的支持之下也日臻完善。