Choose the correct verb form in each of the following sentences.

While Lan ___________ as a volunteer in the countryside, she met an old friend.
1. was working
2. worked
I was revising for my civics class when my dad _______ me about the volunteer Job.
1. was telling
2. told
We saw many unhappy children while we __________ people in remote areas.
1. were helping
2. helped
He was sorting the donations when he ____________ how generous people were.
1. was realising
2. realised