Complex sentences consist of a dependent (a clause that cannot stand alone as a sentence) and an independent clause. They are great for showing a hierarchical relationship between two heavily linked ideas. Commonly (but not exclusively), a participle (often, the –ing or -ed part of the verb) is used to introduce a dependent clause.
Note: whilst compound sentences cannot be reversed, complex sentences often can (with adaptation).
Complex SentenceAfterthe probeis placedin the cylinder,itis usedto measure the flow.
SFL descriptionCircumstanceParticipantProcessCircumstanceParticipantProcessCircumstance
TG descriptionSubordinating conjunction indicating dependent clauseSubject Definite Article, NounFinite, passive verbAdverbial clause of locationPronounFinite verbVerb in the infinitive, object noun clause, independent noun clause
Up to the comma is a dependent clause