Write an argumentative essay. The national civil service examination refers to the civil service examination of the central and state organs. The time is relatively fixed, and it is generally concentrated in the month of10-1,which is referred to as the "national examination". National tax refers to the national tax system, also known as "central tax", which is symmetrical with "local tax". National tax is collected by the IRS system and is a fixed source of income for the central government.