零冠词怎么用?比如：on sunday,they often go to church to hear music.为什么不是on sunday,they often go to the church to hear music.或者on sunday,they often go to a church to hear music

零冠词怎么用?
比如：on sunday,they often go to church to hear music.为什么不是on sunday,they often go to the church to hear music.或者on sunday,they often go to a church to hear music