还原倒装句

A glass container from which a tiny soft light came was on the laboratory bench.
主句是 A glass container was on the laboratory bench。定语从句是 from which a tiny soft light came，修饰container 的，原句的从句也用了倒装，现以全部还原为正常语序。

A glass container from which came a tiny soft light was on the laboratory bench.
其中from which引导的是定语从句。这句话的主语是a glass container，谓语动词时was，on the laboratory bench是介词短语。

A glass container ---主语
from which came a tiny soft light ---定语从句修饰主语
was on the laboratory bench. ---谓语： 系动词+表语（介宾结构）

A glass container from which a tiny soft light came was on the laboratory bench.