How to write 开朗开朗

to open (transitive or intransitive); (of ships, vehicles, troops etc) to start; to turn on; to put in operation; to operate; to run; to boil; to write out (a prescription, check, invoice etc); (directional complement) away; off; carat (gold); abbr. for Kelvin, 开尔文; abbr. for 开本, book format