He told his friends that he ___ what he was reading at the same time the day before.
We should do more such exercise in the future, I think, __________ we did yesterday.
This photo of mine was taken __________ stood the famous twin-tower before the 9.11 event.
Though they met for the first time, they talked __________ they were good friends.
The medicine works more effectively __________ you drink some hot water after taking it.
It will be a long time __________ we finally solve the problem of pollution.