It was not _____ she took off dark glasses _____ I realized she was a famous film star.[ ]

As the prisoner had been ______from the outside world for twenty years, he had no idea what the outside world was like.

I think he is taking an active part in social work.–I agree with you ____.

The fifth generation computers, with artificial intelligence, _____ and perfected now

_____ you at school yesterday—No, I _____ at home.