As is the custom, police forensic experts carried out a painstaking search of the debris.
像往常一樣，警方的.法醫專家對殘骸進行了仔細的查看。
The mastery of a language requires/ needs painstaking effort.
要學好一種語言，必須下苦工夫。
I don't know how to make polite conversation.
我不曉得怎么說應酬話。
He had always been polite ─ she couldn't fault him on that.
他總是彬彬有禮——她在這方面對他無可指摘。