根据下列句子的句意、汉语提示或英语解释,写出空白处所缺单词的正确形式;每空一词.
After so long without any word from David, Mary was starting to (give up) hope.
Mid﹣Autumn Festival is a special time for families and it is on the 15th day of the eighth lunar month.
The official language of China is Putonghua, the foreigners usually call it Mandarin.
He who has not climbed Great Wall is not a true man.
People around the world are working on (reduce) the causes of global warming.
At the very heart of Beijing,the Palace Museum is China's largest of all the ancient
(building).