Research in foreign language teaching involves a lot of variables, such as dependent variables, independent variables, moderator variables, control variables, and intervening variables.

外语教学研究往往会牵涉到许多种变量，但主要的有这样五种，即因变量、自变量、调节变量、介入变量以及控制变量。

youdao

The third variable, for instance, a moderator or a mediator, is a variable that influences relationship between another two variables.

第三变量指影响另外两个变量之间关系的变量，即调节变量和中介变量。

youdao