A clause is a part of a sentence. If there is more than one clause in a sentence, one becomes MAIN and the other SUBORDINATE.
The main clause can stand on its own whereas the subordinate clause cannot. The subordinate clause starts with a conjunction which sends the verb to the end of the clause.
If the subordinate clause comes first, it is followed by a comma and then the main clause which starts with a verb – this becomes the VERB – COMMA – VERB construction. (VCV)
Wenn das Wetter schlecht ist, fahre ich mit dem Bus zur Schule.
V C V
Now try the exercise in this document: