Coordinating conjunctions simply link ideas. Subordinating conjunctions, on the other hand, also establish a more complex relationship between the clauses. They suggest that one idea depends on another in some way. Maybe there is a cause-and-effect relationship between the two. Or maybe the two clauses simply show a chronological development of ideas.
Remember that in most cases the same clauses that are connected by a coordinating conjunction can also be connected by a subordinating conjunction. There is really no difference in meaning; however, the grammar is a bit different.
Study the examples given below.
- He had not received any formal training in engineering. He was a brilliant mechanic.
These two clauses can be combined using the coordinating conjunction but.
- He had not received any formal training in engineering but he was a brilliant mechanic.
We can also express the same idea using the subordinating conjunction though / although.
- Although he had not received any formal training in engineering, he was a brilliant mechanic.
The rules of punctuation are very important when we use subordinating conjunctions to join clauses. As a general rule, a subordinate clause that comes at the beginning of a sentence should be separated from the other clause with a comma. You can omit the comma when the subordinate clause goes after the main clause.
- Since he had not applied in time, he didn’t get the job. (Here we use a comma to separate the subordinate clause from the main clause.)
- He didn’t get the job because he hadn’t applied in time. (Here we do not use a comma because the subordinate clause goes after the main clause.)
