请根据句意从方框中选出合适的词，并用其适当形式填空，使句子通顺

…important    culture    active    thirty-three    necessary…

1. The principal gave us a talk on the            of protecting the environment yesterday.

2. All of us are grateful to him because he always            helps us solve problems.

3. It’s             to tell him the details of the trip. He won’t go with us tomorrow.

4. There are many history and              differences between China and England.

5. ―Who is the              President of the USA?  

―Harry S. Truman.

2010年7月，世界遗产大会决定将（）从《濒危世界遗产名录》中删除。

A.厄瓜多尔的加拉帕戈斯群岛

B.阿塞拜疆的巴库城墙及城内的希尔凡王宫和少女塔

C.阿尔及利亚的提帕萨考古遗址