lis 11

. Phong Nha - Bang can be compared to a huge _____ museum

• natural
• technological
• historical
• artificial

Phong Nha- Ke Bang mountain can provide a lot of ________ information about the Earth's geological developing through various periods

• geographic
• historical
• astronomical
• geological

fill in the blanks:

One geological characteristic to notice here is the system of ____ rivers, grottos and caves in the limestone mountains.

• underground

• overhead
• subterranean
• aerial

Phong Nha-Ke Bang is famous for its vast _________

• mountain range
• cave system
• desert
• waterfall

 If you enjoy mountain climbing, there are some steep mountains over 1,000 metres high, which can be a real ______ for adventurous climbers

• opportunity
• barrier
• obstacle
• challenge