I am worker 为什么要在worker前加a?

I am worker 为什么要在worker前加a? 看下面 I am a worker 对a worker提问 I am an officer worker. I am a worker,I work in the factory. I am from a worker\'s family是什么意思 I am going to be a worker.(改为同义句) 我是一个抛光工怎么翻译,是I am a polish worker.还是I am polishing worker.还是 worker I am an office worker是什么意思 I am a social worker. I wanted to tell everyone about my ver I work in factory.I am a worker.里的work是什么意思什么词性、? I____ a worker,but now i am an actor.A used to being B was u