* Deferred expense represents cash paid in advance to vendors, such as technology service expense, consultant expense and compliance expense, which would be amortized according to their respective service periods.

7.    PREPAYMENTS AND OTHER CURRENT ASSETS (continued)

** Loans to the third parties as of December 31, 2021 mainly consist of the free interest and due on demand loans of US$7,965 to Bee Computing which engages in the research and development of cryptocurrency mining chips and mining machines. The preexisting loans were effectively settled on the acquisition date. See Note 4 for detail discussion.

*** Prepayments for long-term assets mainly consist of the prepayments to vendors in connection with the research and development of cryptocurrency mining chips and mining machines.