堅持

to persevere with / to persist in / to insist on

strong / solid / firm / unyielding / resolute

to hold / to grasp / to support / to maintain / to persevere / to manage / to run (i.e. administer) / to control

to persevere unremittingly (idiom); to keep going until the end

to press on

to stick to sth without change (idiom); to persevere