We mustn't pretend to know what we don't know.
我们不要不懂装懂。
Why didn' t you show up at the meeting yesterday ?
昨天的会你怎么没来?
How much money I earn is none of your business.
我挣多少钱与你无关。
The boxer has fought many opponents.
该拳手已与许多对手交锋。