a small part of a much bigger problem
небольшая часть гораздо более крупной проблемы (nebol'shaya chast' gorazdo boleye krupnoy problemy)
"The data error we found is just the tip of the iceberg."
"Ошибка в данных, которую мы нашли, это только верхушка айсберга." (Oshibka v dannykh, kotoruyu my nashli, eto tol'ko **verkhushka aysberga**.)
the moment when a change becomes unstoppable
to have an extremely enjoyable experience
to recover and be healthy again
to create or develop trust in a relationship
to stop a vehicle at the side of the road
to start something energetically and successfully