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PREPAYMENTS, NET (Details) - USD ($)
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Notes to Financial Statements      
Prepayments $ 2,065,410 $ 487,841  
Allowance for doubtful accounts (147,630) (188,264) $ (127,740)
Total prepayments, net $ 1,917,780 $ 299,577