Zhitong Financial APP learned that on May 8, the Shenzhen Stock Exchange sent a letter of inquiry to 300175.SZ about the company's 2021 report. The inquiry letter pointed out that Longyuan shares reported in 2021 that at the end of the reporting period, the company's book balance of accounts receivable to customer 1 was 65.4 million yuan, with 13.15% of the provision for bad debts separately; at the end of 2020, the book balance of accounts receivable for this customer was 39.19 million yuan, and 9.41% of the provision for bad debts was made on a single basis. At the end of the reporting period, the company's book balance of accounts receivable to 37 customers was 54.76 million yuan, accounting for 100% of the provision for bad debts. The Shenzhen Stock Exchange asked Langyuan shares to supplement the age structure of overseas accounts receivable and the proportion of bad debts, and to supplement the adequacy of provision for bad debts in the light of the impact of the overseas epidemic, the performance ability of major customers, the reporting period and the repayment after the period.