It is required that no smoking ______ in the school.
The reason _______ he was late again was that he was caught in a traffic jam in the rush hour.
His glasses, _______ he could see nothing, was taken away by a naughty boy.
The computer, _______ he paid ¥3,000, was once owned by his uncle.
In the past we lost many chances, _______ we paid little attention.
The pen, _______ I had been writing for ten years, was broken.