The TV play series The Revolution of 1911, broadcast on CCTV1 lately, is ________ the 100th anniversary of The Revolution of 1911.
As birthplace of Huaxia civilization,Xi' an is city with a long history and abundant cultural relics.
If you have any difficulty ____ how to skate, you can turn to Jacky.
He is such a good teacher ______ we all respect.
They are talking _______ they were old friends.
____ it is to skate on real ice!