求翻译：凭以推测经济系统（或其相关变量）在未来可能出现的状况，亦即预测经济系统（或其相关变量）的走势，是我们建立经济计量模型的主要目的。而基于随机变量的历史和现状来推测其未来，则是我们实施经济计量和预测的基本思路。这就需要假设随机变量的历史和现状具有代表性或可延续性。换句话说，随机变量的基本特性必须能在包括未来阶段的一个长时期里维持不变。否则，基于历史和现状来预测未来的思路便是错误的。是什么意思？

With, that is, to predict the trend of the economic system (or variables) to speculate that the situation of the economic system (or variables) that may arise in the future, we have established the main purpose of the econometric model. Based on the history and current status of the random variables

In inferring the economic system (or its related variables) that can occur in the future, i.e. forecast economic system (or its related variables) the trend we have set up the major econometric model. Based on a random variable and the history and the status quo to speculate the future, it is our im

To speculate that economic system (or its associated variables) that may occur in the future, which forecasts economic system (or its associated variables) movement, is our main purpose of econometric models. Based on the history and present situation