lurking presence

介词提前应该不仅仅限于从句中有不及物动词,只要是关系代词需要和介词搭配,或者谓语动词需要和介词搭配的情况
在定语从句中,一般有两种情况会在关系代词前出现介词：
1、与先行词有关的介词可以放到关系代词前,如：
I won't forget the days in which we worked together.(因为in the days,所以 in which)
2、与定语从句中的谓语动词相关的介词会放到关系代词前,如：
The boy about whom they often talk is very kind.(因为talk about,所以about whom )
注：第二种情况是完全可以将介词放到原有的位置（定语从句的谓语动词后）,这时关系的范围就大了很多,如The boy whom/who/that/不填 they often talk about is very kind.
如果介词在关系代词前,关系代词要么是which（先行词是物）,要么是whom（先行词是人）.
希望能对你有所帮助.
以上复制自sdm_a1的回答
补充,可以理解成状语前置

你为什么在走廊里偷偷摸摸?

1. 潜在变数(Lurking variable):指对研究中其他变数间的关系有重要影响,却没有被列入研究范围的变数.（要么因为此存在变量不为人知,或者它的影响被认为是可以忽略而其实不能忽略,或者是数据无法获得）
2. common response有点像协同作用的感觉：指潜在变数同时影响解释变量（x）和反应变量（y）.如果想探索x与y的关系,必须考虑到a对x和y同时都有影响.eg.x=hours of sleep, y= higher grades, a= courseload.
希望能帮到你哈,记得采纳哦~

每个人都戴着面具过,而隐藏在他们面具后的真实却无从知晓.

A lurking variable is a variable that has an important effect on the relationship among the variables in a study but is not included among the variables studied
Common response:Both X and Y respond to changes in some unobserved variable.All three of our examples are examples of common response.
Ice cream sales and shark attacks both increase during summer.
Skirt lengths and stock prices are both controlled by the general attitude of the country,liberal or conservative.
The number of cavities and children's vocabulary are both related to a child's age.