班门弄斧 is a Chinese saying that means "to show off one's skills before an expert". It comes from a story in Chinese history in which a man named Fan Li showed off his sword-fighting skills to the legendary strategist and statesman, Sun Bin, who was said to be an expert in military strategy and tactics.

Here are some examples of how this saying can be used in English:

"John always likes to 班门弄斧 in front of his boss, trying to impress him with his knowledge and skills."

"Sally's 班门弄斧 at the company meeting was a bit over the top. She didn't need to show off so much to prove her worth."

In Chinese, these sentences would be translated as:

"约翰总喜欢在老板面前班门弄斧，试图用他的知识和技能给老板留下深刻印象。"

"莎莉在公司会议上的班门弄斧有点太过了。她没必要表现得如此出众来证明自己的价值。"