协方差

Based on the study of scholars at home and abroad and from the point of theoretical and empirical study, this paper analyses the impact of foreign trade and FDI over China's business cycle using many econometric methods such as Unit Root Test, Co-integration Tests, Granger Test, Pulse-response Function and variance decomposition based on VAR model and draws the conclusion as follows:Firstly,there is a close relationship among foreign trade, FDI and business cycle. Foreign trade and FDI are the important transmission channel of the economic cycle. Secondly, the impact to economic fluctuation from foreign trade is greater than that of FDI. Thirdly, In the long time, there is fine interactive circulation among foreign trade, FDI and economic growth. When the short-term deviation from equilibrium happens, there is a self-balanced mechanism in the system.Fourthly,the active effect outweighs the negative effect which the foreign trade and FDI brings.

本文在国内外学者研究成果的基础上，从理论和实证两个方面，运用单位根检验、协整检验、格兰杰因果检验、基于VAR模型的脉冲响应分析及方差分解等计量经济学的方法，从比较的角度分析了对外贸易及FDI对我国经济周期波动的影响，得出结论如下：首先，对外贸易、FDI与我国经济的波动有着显著的关系，二者是传递经济周期的重要渠道；其次，对外贸易对我国经济波动的影响要大于FDI的作用；第三，长期看我国FDI、对外贸易和经济增长之间形成良好的互动循环，当系统短期内偏离均衡状态时，系统存在一个自我均衡机制；第四，对外贸易及FDI对我国经济周期波动产生的积极效应要远大于它所带来的负面效应。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了