Ⅰ、1、long
2、old
3、high
4、tall
5、wide
6、thick
7、deep
Ⅱ、1、the oldest
2、the longest
3、higher
4、the deepest
5、wider
Ⅲ、1、Mountain climbing is one of the most dangerous sports.
2、The Himalayas run along the southwestern part of China.
3、It's hard to take in air as you get near the top.
4、We should never give up trying to achieve our dreams.
5、Humans can sometimes be stronger than the forces of nature.