Final answer:
The statement is true. Adverbs ending in LY do not require a hyphen when used with a participle, as the sentence will make sense without it.
Step-by-step explanation:
The statement that we do not use a hyphen between an adverb that ends in LY and a participle is true. When the adverb ends in LY, it clearly modifies the verb and not the noun, thus forming a clear sentence without the need for a hyphen to clarify the relationship between words. A test to confirm the correctness is to remove the participle (e.g., completed, planned) from the sentence. If what remains still makes sense, there is no need for a hyphen.
Here is an example for clarification:
- Correct: The beautifully painted portrait.
- Incorrect: The beautifully-painted portrait.
When 'beautifully' is used with 'painted', it is clear that 'beautifully' is an adverb modifying the action of painting, not the portrait itself, therefore no hyphen is needed.