Grammar for Everyone - Barbara Dykes 2007

Adverbial clause of place
Introduction
Part II The parts of speech

This clause tells you more about where something happens.

Finite verbs:  swept, were building

Main clause:  she swept the shed

Conjunction:  where

Subordinate clause: the spiders were building webs

Adverbial clause of place, modifying the verb ’swept’ in the main clause.

Complex sentence