英语把一个句子改为否定句时加什么否定词,把这些否定词加以使用说明

在系动词、助动词或情态动词后加never,hardly,little,few,no one,nothing,nobody,neither,none,nowhere等否定含义的词,句子变成否定句.如 She has never been to London./ He could hardly walk by himself because ...