IV. Complete each sentence with one suitable word. The first letter of each word is given: 1. A local man named Ho Khanh d***isco****ver....................... Son Doong Cave in 1991. 2. Within a few years, Phu Quoc Island has changed into a tourist p************. 3. E************ often travel to new places, discovering amazing sights and experiencing different cultures. 4. The ecosystem in Con Dao National Park is very d************ with thousands of species, including marine life. 5. O Quy Ho Pass is a popular d************ for travelers who seek adventure and natural beauty on their Sapa trip.