Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the following questions from 26 to 31.
CAVE OF SECRETS: THEN AND NOW
Hidden in the jungle of central Việt Nam, Son Doong Cave, which means ‘mountain river cave’, was formed millions of years ago. It was unearthedby HồKhanh, a local man, in 1991, but it wasn’t until 2009 that the cave was explored for the first time. However, a group of British cavers had to stop after 4 kilometers because a great wall blocked their way. One year later, they returned to continue their expedition.
Then they found two spectacular natural skylights deeper in the cave. An explorer said, “Watch out for dinosaurs” as his partner walked into the light. In this dreamy place, prehistoric reptiles seem likely to appear at any moment. There are even misty clouds – the cave is giganticandit has its own weather system. After a two-day climb, they literally saw light at the end of the tunnel as they reached the cave’s exit. Nine years later, three British divers discovered an underwater tunnel connecting the cave with another one called Thung Cave. When they’re officially connected, 1.6 million cubic meters will be added to the cave volume. The trio planned to return in April the following year. It’s awe-inspiring that our largest cave is still being explored.
(Adapted from SGK Explore English 9)
