We use when as a conjunction meaning 'at the time that'. The clause with when is a subordinate clause (sc) and needs a main clause (mc) to complete its meaning. If the when-clause comes before the main clause, we use a comma.

Are clauses sentence structure?

A simple sentence consists of only one clause. A compound sentence consists of two or more independent clauses. A complex sentence has at least one independent clause plus at least one dependent clause. A set of words with no independent clause may be an incomplete sentence, also called a sentence fragment.

What are the 4 types of sentences formed by clauses?

There are four types of sentences: simple, compound, complex, and compound-complex. Each sentence is defined by the use of independent and dependent clauses, conjunctions, and subordinators.