Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions. Son Doong Cave Located in the limestone mountains of Phong Nha - Ke Bang National Park. Son Doong Cave was first found in 1991 by Ho Khanh, a local man. In 2009, the cave was explored and published by a group of scientists from British Cave Research Association. Son Doong Cave was formed from 2 to 5 million years ago, when the river flowed through the limestone mountain area and was buried. The water eroded limestone and created an underground tunnel. In soft limestone areas, the collapse of tunnel ceiling formed large holes which became giant domes afterward. The cave is about 200m high, 200m wide and at least 8.5km long. Especially, Son Doong consists of two entrances, which is unique among explored caves in Phong Nha - Ke Bang National Park. Exploring the cave, visitors were surprised with spectacular scenery of numerous stalactites of which some giant stalagmites are more than 70 metres high. Deep inside the cave exists a grandiose tropical jungle called “Garden of Eden" by the explorers. The jungle is home to a diversified system of fauna and flora. Besides, the cave possesses a 2.5 kilometres underground river. Not far from the “Garden of Eden” lies an enormous “pearl collection” consisting of tens of thousands of small stone pieces in dry ponds, contributing to magnificent beauty of the cave. Question 32. The thing that makes it different from other caves in Phong Nha – Ke Bang National Park is A. the two entrances into the cave B. its discovery by a local man C. stalactites and stalagmites D. large holes in the ceiling Question 31. All of the following are the wonderful features of Son Doong Cave EXCEPT A. tropical jungle inside with the biodiversity B. spectacular scenery of numerous stalactites and stalagmites C. a river flowing over 2.5 kilometers outside the cave D. a diversified system of fauna and flora Question 30. The most important feature of “Garden of Eden” is A. the biodiversity B. giant stalagmites C. the river below D. the biggest length Question 29. The reason why Son Doong Cave was formed is that A. the limestone areas were soft B. the river was buried in the limestone mountains C. it only happened from 2 to 5 million years ago D. an underground tunnel was buried in the area Question 28. When was So Doong Cave first discovered A. in 2009 B. in 1991 C. 5 million years ago D. 2 million years ago