* either .. or: is a construction we use to show there is a choice between two different things, but you can only choose one, not both. It means one or the other, but not both.
* neither...nor: is a construction we use to show that two or more things are not true or possible. It means not the first object and not the second object are behaving in a certain way. see more here
Examples:
Her hair was neither long nor short.
I could neither laugh nor cry.
You either pass or fail your test.
There's no third option, you know.
He did not find the key either on or under the mat.
Quiz- Both ... and, neither ... nor, either ... or.