题目

There is a famous story about British poet Samuel Taylor Coleridge. He was writing a poem when he was interrupted by a knock at the door. This was an age before telephones. Someone was delivering a message. When Coleridge got back to his poem, he had lost his inspiration. His poetic mood had been broken by the knock on his door. His unfinished poem, which could otherwise have been a masterpiece, would now never be more than a little piece. This story tells how unexpected communication can destroy an important thought, which brings us to the cell phone. The most common complaint about 已知：，则=    ．