How can you lift an elephant one-handedly?
A definition of one-handedly from Oxford dictionaries:
With or using only one hand.
Explanation of why it works ...
Some English grammar
There is a reason why this sentence—in contrast to the Original Poster's more intriguing one—is unambiguous.
In the original example, the preposition phrase with one hand could be modifying the verb phrase lift an elephant, or it could be modifying the noun elephant. One reason for this is that preposition phrases in English can modify verb phrases:
- [[climb mountains] at the weekend]
And they can also modify nouns:
- [[parties] at the weekend]
The example in this answer post, on the other hand, uses an adverb to modify the verb phrase lift an elephant. Adverbs can freely modify verb phrases:
- It quickly evaporated
- It evaporated quickly
But adverbs can't premodify nouns:
- *It was a quickly evaporation (ungrammatical)
And they rarely postmodify them either:
- *It was an evaporation quickly. (ungrammatical)
And that's why the adverb one-handedly can only be modifying the verb phrase lift an elephant and not the noun phrase elephant.
Notes for grammar junkies
It used to be commonly thought that adverbs never modified nouns. However, recent work in corpus linguistics has shown this to not be true. Certain types of adverbs can very occasionally postmodify certain types of noun:
- The riots recently are going to cause problem for years to come.
Here we see recently modifying the noun riots. This can't be a sentence adverb, because the sentence as a whole is referring to the future, whereas recently refers to the recent past.