1. Check whether the taxable income has been fully taxed. The turnover of the business tax in the construction industry includes the project payment (i.e., the cost of the project) collected by the construction and installation enterprise from the construction unit, as well as various charges collected outside the project payment. During the review, the engineering contracting contract and tax return should be referred to, combined with the "engineering settlement income" account, to see whether the taxpayer's "project payment settlement statement" confirms that the amount has been fully declared for taxation.