5.91 'at' for relating events

You can also use 'at' when you want to relate the time of one event to another event such as a party, journey, election, and so on.

• I had first met Kruger at a party at the British Embassy.
• She represented the Association at the annual meeting of the American Medical Association in Chicago.
• It is to be reopened at the annual conference in three weeks' time.

5.92

'At' is also used with ages, stages of development, and points within a larger period of time:

• At the age of twenty, she married another Spanish dancer.
• He left school at seventeen.
• At an early stage of the war the British Government began recruiting a team of top mathematicians and electronics experts.
• We were due to return to the United Kingdom at the beginning of March.