II. Practical exercises: Change these sentences into the passive voice 1. They know that Halong Bay was recognized as a World Heritage Site by UNESCO in 1994. 2. They claim Phong Nha – Ke bang can be compared to a huge geological museum. 3. People expect the government will have measures to protect and preserve our man-made wonders. 4. They report that thousands of visitors come to enjoy breathtaking views of Halong Bay every year 5. They thought that in the 17th century the Viet people took over the temple tower, calling it Thien Y Thanh Mau Tower