某些副词和副词短语,主要是一些含有限定或否定意义的副词和副词短语,为了表示强调可放在句首,这时后面应跟动词的倒装(即疑问)形式。这类副词或副词短语中最重要的有:
hardly ever
on no account
hardly…when
only by
in no circumstances
only in this way
neither/nor
only then/when
never
scarcely ever
no sooner…than
scarcely…when
not only
seldom