mantener.

to keep

Mantenga la tapa cerrada, por favor.

to maintain, to support

Yo mantengo a mis hijos.

to sustain, to preserve, to retain, to uphold

to maintain, continue, to keep up

Mantengan el buen trabajo.

to stay, to remain

to maintain, to keep, to stay, to remain

Me voy a mantener despierto toda la noche estudiando la gramática española.

to stand, to hold, to remain, to continue (e.g. hold firm, stand strong, stand together, stand on one's feet)

Debemos mantenernos firmes exigiendo libertad.

to stick to (e.g. stick to one's guns)

to be maintained, to be retained, to be sustained