People don't ask unmarried people Why are you single?.
人们不会问未婚的人“你为什么不结婚?”。
What were you doing when I called you on the telephone?
当我打电话给了你时,你正在做什么?
The administrative overheads of a business are low to the extent that everyone working in the business can be trusted to behave in a way that best promotes the interests of the firm.