ADJ. major | minor, small | life-saving, vital | emergency | routine | delicate a delicate eye operation | exploratory | surgical, transplant | heart, knee, etc.
VERB + OPERATION have, undergo He had an operation to remove a tumour. | come through, survive She came through the operation very well. | carry out, perform the surgeon performing the operation
PREP. during a/the ~ She woke during the operation. | ~ for an operation for a kidney problem | ~ on a major operation on his heart
2 organized activity
ADJ. big, large-scale, major, massive | covert, undercover | combined, joint | tricky a tricky rescue operation | intelligence, military, naval, police | guerrilla | clean-up, drilling, mining, mopping-up, offensive, peacekeeping, relief, rescue, salvage, security UN troops supervised the relief operations. | banking, building, business restrictions placed on business operations
VERB + OPERATION begin, launch, mount, undertake The authorities launched a massive security operation in the city. | carry out, conduct | supervise
PREP. during a/the ~ during joint military operations
PHRASES a theatre of operations (= where military operations take place)
3 fact of sth functioning
ADJ. effective, efficient, smooth | day-to-day the smooth day-to-day operation of the department
VERB + OPERATION come into A ceasefire came into operation in May. | bring/put sth into | cease The factory will cease operation at the end of the year.
PREP. during ~ The machine can get very hot during operation. | in ~ The current tax system has been in operation for ten years.
PHRASES in/into full operation the only reactor in full operation