you did a good job 请问这里为什么要用冠词A

you did a good job 请问这里为什么要用冠词A you did a good job. great!you ____ a good job.答案是did.为什么? you did do a good job you did a good job 同义句 You all did a good job. you did a good job today You really did a good job!这句话是什么意思 Did you do a good job 改为肯定句 You did a good job!keep at it please Do you want a busy but exciting job 这里为什么要用exciting不用excited did a good job怎么读