Many athletes are clear that the Olympic Games are the only time ________ they will be watched by thousands of millions.
—How about going for a picnic this weekend? — Why not? _________.
I can’t remember the day ______ we first met in China.
The boy ________ the father worked in the USA is Jack.
Is this the school _______ you worked last year?
Is this school _____ you visited last year?