a. Once I graduate... • I took a gap year before starting a job. • I will take a gap year before starting a job. I'm taking a gap year before starting a job.
b. We will keep on doing sport... when we are older. when we were older. when we have been older.
c. We will go on holiday... • once we finish our work. • once we have finished our work. • once we finished our work.
d. "When will I have my job interview?" He would like to know... when he has his job interview. when he will have his job interview. when he had his job interview.