找出下列句子的一處語法錯誤：

　　According to some economists, a financial crisis is unavoidable event for the global market and it happens every several years as a result of long-term economic development.

　　適用考題：

　　In times of economic crisis, local governments often reduce the money they spend in some areas. In your opinion, if a local government is facing economic problems, which of the following areas should it spend less money on? a. libraries b. public transportation c. police. (2014.1.18)

　　答案：

　　According to some economists, a financial crisis is an unavoidable event for the global market and it happens every several years as a result of long-term economic development.