俄语 ⇄ 英语 +

как это часто случается 强调
一般	as (they) very often (are; If the natural drives are insufficient, as they very often are, then the pressure can be artificially maintained by injecting water into the aquifer or gas into the gas cap. ArcticFox)
数学	as is often the case; as often happens
как это часто случалось
修辞格	as was often the case (sophistt)