первым долгом
см. тж. в основном; в первую очередь; во-первых; прежде всего
• First and foremost, Britain has vast energy reserves.
• What they did first of all (or first off) was to call the local geologist.
• The final acceptance of this interpretation will depend in the first instance (or place) on confirmation of their results.
Источник:
Русско-английский научно-технический словарь
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