1.it's (a) good exercise.为什么有a

1.it's (a) good exercise.为什么有a It's good exercise.为什么good前不用加a? _____ regular exercise is very important.It’s never a good i 英语翻译这句话怎么翻译.it's never a good idea to exercise too close to 首字母填空： It`s a good way to exercise to s___ slim. this is good exercise 为什么不是this is a good exercise ? It's for a good 2道小学英语的选择It's good _______ exercise every day.A.to take B.ta it's good exercise改为否定句 It's good for exercise every It's good exercise.中exercise做什么语, It's a good place to live in.为什么有的地方有in有的没有