A. DIFFERENT B. SATISFIED C. EXCITING D. AVAILABLEB. READ THE PASS...

26) A. different B. satisfied C. exciting D. available

B. Read the passage and choose the best answer for each question.

Son Doong Cave, a three-million-year-old cave in central Vietnam, is located in the heart of the UNESCO-listed

Phong Nha-Ke Bang National Park in Vietnam's Quang Binh province. It was first discovered in 1990 by Ho Khanh, a

local farmer who was seeking shelter from a passing storm in the jungle. He noticed clouds and the sound of an

underground river gushing from a large hole in the limestone, and reported his findings to the British Caving

Research Association (BCRA), who were stationed in Phong Nha at the time. Unfortunately, Ho Khanh lost his

bearings during his return, and the exact location of the cave remained lost for 18 years. In 2008 while hunting for

food he stumbled across the entrance again, and returned the following year with Howard and Deb Limbert from the

BCRA. They began the exploration of the cave, and in 2010 determined it to be the largest ever discovered in terms

of the size of its cross-section. Stretching more than five kilometers long and reaching heights of 200 meters and

150m wide, Son Doong Cave is large enough to house an entire New York City block. With a total

measured volume of 38.5 million cubic meters, this comfortably surpasses Deer Cave in Malaysia, which

was considered to be the previous record holder. In 2013, it was opened to the public for the first time. Only 10

customers per departure are permitted. Tours run once per week between February to August per year.