A subordinating conjunction joins a subordinate clause to a main clause.
The following is a list of the most common subordinating conjunctions.
|after||how||till ( or 'til)|
|as if||in order that||when|
|as long as||lest||whenever|
|as much as||now that||where|
|as soon as||provided (that)||wherever|
An adverb clause is always introduced by a subordinating conjunction. A noun clause and adjective clause sometimes are.
Adverb clause: Before you go, sign the log book.
Noun clause: He asked if he could leave early.
Adjective clause: That is the place where he was last seen.
A subordinating conjunction is always followed by a clause. Many subordinating conjunctions can be other parts of speech.
Adverb:Jill came tumbling after.
Preposition: Jill came tumbling after Jack.
Subordinating Conjunction: Jill came tumbling after Jack had fallen.