他跟顾客打招呼时直呼其名，并问他们身体可好。He greets customers by name and enquires about their health.他向他们挥一下手，热情地笑着向他们打招呼。He greeted them with a wave and a broad smile.他们俩都笑着跟朋友们点头打招呼。Both of them smiled and nodded at friends....
长久以来，市场有一块巨大的空白。For too long there was a huge gap in the market.他帮我们填满知识上的空白.He helped us to fill in a big gap in our knowledge.这有助于弥补我们知识上的空白.This will help to fill a vacancy in our knowledge....