'Do' And 'does' are the two forms from the current indefinite tense in the verb 'to complete.' Which one you'll use will typically rely on the sentence's subject matter. Their utilization is sort of equivalent, apart from just one instance where You need to use 'do' instead of 'does.' https://financefeeds.com/btc-news-flash-bitcoin-solaris-presale-enters-final-phase-at-7-last-chance-before-233-jump-to-20-at-launch/