Question

你说 当从句主谓宾成分完整时用where，不完整则用which, that. 能举个例子么 帮帮忙 谢谢了！

Answer 1

要看在句子中充当的成分来选择关系词。
1.this is the place where i worked befor.
这句中，从句的谓语动词是work,为不及物动词，也就是说从句无需有宾语，主谓成分完整，所以选where 做状语
2.this is the place which /that i visited last time.
这句中visit为及物动词，也就是说从句中需要有宾语，所以有关系代词which /that 作为宾语、

Answer 2

这句话是谁说的，意思不错，表达不精确
关系词的选择要受到其在从句中充当的成分的影响
如果从句成分完整，只能选关系副词作状语
否则可以用关系代词充当主语或宾语
举个定语从句的例子
This is the village where I lived.【I lived主谓完整】
This is the village which I lived in.【I lived in缺宾语】