用所给单词的适当形式填空。 1. When we visit the Tian'anmen Square, we are _____ (excite) about it. 2. Have you _____ (be) to the Great Wall? 3. It's about 6,400 _____ (kilometer) long. 4. Qomolangma is the _____ (high) mountain in the world. 5. Have you heard of the Empire State _____ (build) which is in the centre of New York?