buy this shirt or either buy the dress.
i can either buy this shirt or the dress.
she is nasty. she is also selfish.
she is neither nasty nor selfish.
she is both nasty and selfish.
she is either nasty or selfish.
she is nasty and both selfish.
she is stupid. or she is careless.
she is neither stupid nor careless.
she is both stupid and careless.
she is both stupid or careless.
she is either stupid or careless. 