"A dead clock is correct twice a day" nghĩa là gì?

"A dead clock is correct twice a day" = đồng hồ chết thì vẫn đúng hai lần trong ngày -> nghĩa là người sai cũng có khi đúng, dù chỉ tình cờ.

Ví dụ 

"You know how I feel about the mayor, but even I think he's right this time. Even a dead clock is right twice a day."

A former boss of mine used to say that there’s no one without a talent. He went on to buttress his point by noting that “even a dead clock is correct twice a day”. I’ve pondered on this over the years and concluded that he couldn’t have been more correct. When a clock stops working at 2 o’clock; the time it tells is correct at 2 am and 2 pm daily. This remains so even when the clock is left untouched for the next 100 years.