Days of the week
Why can't you come to Sue's birthday party on Thursday?
I go to my grandmother's house on Thursdays.
Why can't you come on Sue's birthday party on Monday?
I have piano lessons on Mondays. / On Mondays, I have piano lessons.
Why can't you come on Sue's birthday party on Wednesday?
I practise hockey on Wednesdays. / On Wednesdays, I practise hockey.