To wander far off the subject; to be completely irrelevant to the main topic.
他的发言完全离题万里，大家听了半天也不知道他到底想表达什么。
His speech completely wandered off the subject; after listening for a long time, no one knew what he was trying to express.
Era:
Modern
Frequency:
Story:
Once upon a time, there was a conceited scholar who was jokingly called 'Doctor'. One day, he went to the market and bought a donkey.
According to the custom of the time, the buyer needed to write a contract for the seller. The scholar spread out a piece of white paper and began to write voluminously, filling three whole pages with superfluous words completely unrelated to the donkey.
The donkey seller grew impatient and urged him to hurry. The scholar, however, calmly replied that there was no rush, as he hadn't even written the character for 'donkey' yet.
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