my father is at work.这里at 为什么他同义于working

my father is at work.这里at 为什么他同义于working My father is at work同义句 My father is at work改为同义句 My father is at work (改为同义句） My father is at work.改为同义句. My father is at work.(同义句转换) My father ___ ____. My father was at work at that time 变为同义句 I am busy working at my lessons.这里的at是不是用错了啊?为什么? 每空填一单词,是两句意思相同.my father is at work.my father is --------- my father is at home(同义句） My father work at the zoo My father is working out at the gym (next week).对括号部分进行提问