---Is this the first time you ______ Xi’an? --- No. But ______ here, the city wasn’t so modern.
—Why does she always ask you for help? —There is no one else _______, is there?
Do you have any idea _______ is actually going on in the classroom?
Mary wrote an article on _______ the team had failed to win the game.
Doris' success lies in the fact _______ she is co-operative and eager to learn from others.
See the flags on top of the building? That was _______ we did this morning.