they were not at work at that time 改成一般疑问句和否定句就改成疑问句，把not删掉
问题描述：
they were not at work at that time 改成一般疑问句和否定句
就改成疑问句，把not删掉
答
一般疑问句who were not at work at that time? 肯定句They were at work at that time
答
一般疑问句： Were they not at work at that time?
否定句：They were at work at that time
答
were they at work at that time?
你这句就是否定句
答
were they at work at that time?
they were not at work at that time .