Answer:
1. The biggest (big) piles of trash on Mount Everest are on the lower areas.
2. Trash is one of the worst (bad) problems on Mount Everest now.
3. Many climbers consider K2, a mountain between Pakistan and China, to be the most difficult (difficult) mountain to climb, not Mount Everest.
4. Ted was the most experienced (experienced) climber on the expedition.
5. Which climber is the farthest (far) from the top?
6. That was the easiest (easy) mountain I've ever climbed.
Explanation:
The superlative form of an adjective or an adverb is used to make comparisons. To form the superlative, you have to add "-est" to the end of most one syllable adjectives or adverbs. For example, in the first sentence "big" changes to "biggest".
However, if the adjective has two or more syllables and the adverb ends in "-ly", you have to use "the most": for example, in the third sentence you have to write "the most difficult".
There are also irregular superlatives, for example, in the second sentence "bad" changes to "the worst".
