Both / Either / Neither Parties
Both ... and
The paired conjunction 'both ... and' is used to introduce dual subjects which take plural verb conjugations.
Both the pin pad and the website technology are cutting edge with that bank.
Both this contract and the old one are negotiable.
Either ... or
The paired conjunction 'either ... or' is used in sentences to show that one or the other is performing an action. Conjugate verbs based on the subject (singular or plural) closer to the conjugated verb.
You can use either my company or my competitor's company for signature verification.
Either payment by check or credit card is acceptable.
Neither ... nor
The paired conjunction 'neither ... nor' is used in sentences giving a negative sense. Neither one nor the other subject does an action. The negative is conveyed by the 'n' in 'neither' and 'nor'. 'Not' is not placed before the verb. Conjugate verbs based on the subject (singular or plural) closer to the conjugated verb.
Neither branch manager nor teller was able to answer why the report was not filed under separate cover.
At the community bank where I keep my money, neither my savings account nor my checking account is earning very much interest these days.
Neither Marina nor the other potential investors are taking responsibility for the cancelled check.
Neither the client nor the company were able to reach an agreement.