Parallel Contruction

Parallel Construction

Both … and

Subjects connected by 'both … and' take the a plural conjugation.
Examples:
Both Alice and Janice attended USC.
Both Jim and Peter are attending the conference in New York this weekend.

Not only ... but also ...

Not only and but also normally go immediately before the words or expressions modified by them.
The place was not only good, but also safe.
She is not only a good wife, but also a good mother.
She speaks not only English, but also French.
Mid position with verb is also possible.
She not only speaks English, but also French.
For emphasis not only can be moved to the beginning of a clause. Note that we use the inverted word order 'not only + auxiliary verb + subject'. But can be left out in some cases.
She was not only sad, but also angry.
Not only was she sad, she was also angry.
They not only need food, but also shelter.
Not only do they need food, they also need shelter.

Either … or

'Either … or' is used in sentences in a positive sense meaning "one or the other, this or that, he or she, etc." Verb conjugation depends on the subject (singular or plural) closest to the conjugated verb.
Examples:
Either Peter or the girls need to attend the course. (second subject plural)
Either Jane or Matt is going to visit next weekend. (second subject singular)

Neither … nor

'Neither … nor' is used in sentences in a negative sense meaning "not this one nor the other, not this nor that, not he nor she, etc.". Verb conjugation depends on the subject (singular or plural) closest to the conjugated verb.
Examples:
Neither Frank nor Lilly lives in Eugene. (second subject singular)
Neither Axel nor my other friends care about their future. (second subject plural)