We all feel         our duty to make City of Wenzhou a better place.

Mr Cooper wanted to buy the house and he told me that      the house cost, it would be      it.

--- Mum, have you seen my mobile phone?---______ you bought last week? I’m afraid I haven’t seen _____．

Nelson Mandela devoted all his life to the struggle of the African people and      of every nation that seeks freedom．

Catherine bought a postcard of the place she was visiting, addressed ___to ____and then posted it at the nearby post office.