HELP !---20 min ESOL speaking and listening lesson

Hello, I have a job interview and I am expected to deliver a 20 minute ESOL session on Entry Level 2/3 speaking and listening. What would you suggest to teach? 20 mins is not really much. The group is also large e.g. more than 2o students aged 18+.
Thanks. Gemma

Do you have much information about the curriculum of the school/institute?

No, but the lesson is tomorrow.