Group 1 - The article discusses the concept of cumulative value-added tax (VAT) sales amount for taxpayers within a continuous operating period of no more than 12 months or four quarters [6] - The operating period is defined as the continuous period of operation during the taxpayer's existence, including months or quarters without sales revenue [7] Group 2 - The article provides contact information for the Ningbo Municipal Taxation Bureau for inquiries related to tax payments [8]