Either: any one of two. Each of two (A garden with a fence on either side) Either…or: introducing two choices (Either you come or I go) Neither: not the one, nor the other. Neither proposal is acceptable. It is normally followed by a singular verb. Neither of them is coming. However, in informal usage the plural is common: Neither of them are coming Both: the two.

So, too, neither, not either, but And + so+ be/do + subject: affirmative Amy is a twin and so is Sue Amy likes dogs and so does Sue And+ subject+ be/do + too: affirmative Amy is a twin and Sue is too Amy likes dogs and Sue does too And + neither +be/do + subject: negative Amy isn’t tall and neither is Sue Amy doesn’t like cats and neither does Sue And + subject + aux + not either: negative Amy doesn’t like cats Sue doesn’t either But + subject + be/ do/aux + not: contrast Amy is outgoing but Sue isn’t Subject + do + not +but+ subject + do Amy doesn’t drive but Sue does