ought to be "vicious circle'.
Although this is a very common mistake of Hong Kong English learners,
it is unacceptable that the mistake is found exist in a profound text book, whose publisher has a number of specialised editors and advisors.
Please be acknowledged.
更新1:
各位人兄, 如果考proofreading時 , 只找到vicious cycle 這個可能錯的字眼,其餘全對, 請立即打「剔」。 hkwaddle小dd, 您的理解能力大有問題,我的原意是「雖然這是香港學習英語的人的常見錯誤,但在一本資深的書內發現這錯誤是難以接受的,因為其出版社有很多學識淵博的編輯和顧問。」