to burn / to cook / to stew / to bake / to roast / to heat / to boil (tea, water etc) / fever / to run a temperature / (coll.) to let things go to one's head
to open / to start / to turn on / to boil / to write out (a prescription, check, invoice etc) / to operate (a vehicle) / carat (gold) / abbr. for Kelvin, 開爾文|开尔文[Kai1 er3 wen2] / abbr. for 開本|开本[kai1 ben3], book format