30p
a) While I was doing/did my homework, I had a good idea.
b) Jim was breaking/broke his leg when he was playing golf.
c) When I arrived, I was going/went into the kitchen.
d) We were finding/found and old box while we were digging in the garden.
e) I was seeing/saw an old friend while I was waiting for the train.
f) While I had/was having a bath, the phone rang.​