They are leaving for an excursion. (change to past tense)
Answers
Present Simple
I usually leave for work at seven in the morning.
Present Simple Passive
Books are left on the desk at the front of the room.
Present Continuous
Mary is leaving for London today.
Present Continuous Passive
The city is being left by thousands this week.
Present Perfect
She hasn't left for the meeting yet.
Present Perfect Passive
The city hasn't been left by everybody yet.
Present Perfect Continuous
She has been leaving reminders around the house for years.
Past Simple
I left for work early yesterday morning.
Past Simple Passive
The magazine was left on the table yesterday afternoon.
Explanation:
Past Continuous
We were leaving for our vacation when they arrived.
Past Continuous Passive
The tourists were being left behind when the tour guide noticed they were missing.
Past Perfect
They had already left home when we got there.
Past Perfect Passive
The ticket had been left behind so he couldn't come.
Past Perfect Continuous
She had been leaving him reminders for a while before he remembered to take out the trash.