Conjunctions which are always used in pairs are called correlative conjunctions. Note that most correlative conjunctions are of the coordinating type.

Examples are: either…or, neither…nor, not only…but also…, not…but, though…yet, both…and, so…that etc.

Either…or

You must either obey me or quit.
Either you or he will have to do this job.
You can have either tea or coffee.

Neither…nor

She is neither intelligent nor beautiful.
I will neither obey you nor quit.
You can have neither tea nor coffee.
Neither Ann nor Mary came.

Not only…but also

Not only Alice, but John also got a scholarship.
He not only tells lies but also misbehaves with everybody.
He teaches not only mathematics, but also history.
She was not only beautiful but also intelligent.

Note that also is very often omitted.

She was not only beautiful but intelligent.

Not…but

The culprit was not John but Peter.
It is not a first class film but reasonably good.
The driver did not stop the vehicle but drove on.

Though…yet

Though he worked hard yet he couldn’t pass.
Though he is poor yet he is happy.
Though he is unwell yet he wants to play.

Note that yet is often omitted in such sentences. Many students commit the mistake of using but instead of yet.

Though he worked hard he couldn’t pass. OR Though he worked hard yet he couldn’t pass. (NOT Though he worked hard but he couldn’t pass.)

Whether…or

I don’t know whether she would come or not.
It doesn’t matter whether he comes or not.
You have to do this job whether you like it or not.

Both…and

He is both intelligent and handsome.
Both the minister and his colleagues visited the site.
He is both a journalist and a statesman.
I both love and respect my parents.

As…so

As you sow, so you reap.
As a father loves his children, so does God love mankind.

So…as

She doesn’t earn so much as he does.
It is not so bad as you think.

So…that

She was so weak that she could barely stand.
The officer was so corrupt that he had to be sacked.
The box was so heavy that I couldn’t lift it.
It was so hot that we didn’t go out.

Such…that

Such was Helen’s beauty that princes from far and near came to woo her.
Such was his performance that the audience was spellbound.
Such was Prince Edward’s love for Ms Simpson that he sacrificed even his crown for her.