求教either和neither单用的谓语单复数情况

-HE

在prep08语法笔记第67页看到说neither（nor）单用的时候，谓语的单复数是看后面跟的宾语的，举了两个例子
1、They were not in Shanghai at that time. Neither (nor) were we.
2、They are not from England. Neither (nor) is she.
但是在Manhattan上面明确说“Note that when the words either or neither are in a sentence alone,( without or or nor), they are considered singular and take only singular verbs.”没有举例。
纠结了，到底哪个对。。
求帮助。