Adjective/Adverb

Grammarian-bot wrote:

I always face problmes with identifying adverbs and adjectives. As per my knowledge, adverbs end in ly but not all of them. I know that in the following sentences, sentence # 2 is wrong but why? Why can't we use smoothly  for wings? Is it beacuse it would mean that whoever shaped the wings did it (act of shaping) smothly rathar that making them smooth (of smooth material/nature)? 1.   Since the 1930’s aircraft manufacturers have tried to build airplanes with frictionless wings, wings so smooth and so perfectly shaped that the air passing over them would not become turbulent The first part "wings so smooth" is an adjective phrase combined with the latter part "so perfectly shaped" which is adverbial in construction. In essence, I would consider this an adverbial phrase as a whole because it modifies the "frictionless wings" 2. Since the 1930’s aircraft manufacturers have tried to build airplanes with frictionless wings, shaped so smoothly and perfectly that the air passing over them would not become turbulent. This is a passively formed adverbial phrase. Is smooth both adverb and adjective? How to identify when it's used as a verb and when as an adjective? Also what's wrong with this sentence? 3.        Since the 1930’s aircraft manufacturers have tried to build airplanes with frictionless wings that are shaped so smooth and perfect that the air passing over them would not become turbulent. This is incorrect because "shaped" is a verb used passively and verb requires adverbs not adjectives. CB

1.   Since the 1930’s aircraft manufacturers have tried to build airplanes with frictionless wings, wings so smooth and so perfectly shaped that the air passing over them would not become turbulent

The first part "wings so smooth" is an adjective phrase combined with the latter part "so perfectly shaped" which is adverbial in construction. In essence, I would consider this an adverbial phrase as a whole because it modifies the "frictionless wings"

2. Since the 1930’s aircraft manufacturers have tried to build airplanes with frictionless wings, shaped so smoothly and perfectly that the air passing over them would not become turbulent.

This is a passively formed adverbial phrase.


Is smooth both adverb and adjective? How to identify when it's used as a verb and when as an adjective? Also what's wrong with this sentence?

3.        Since the 1930’s aircraft manufacturers have tried to build airplanes with frictionless wings that are shaped so smooth and perfect that the air passing over them would not become turbulent.

This is incorrect because "shaped" is a verb used passively and verb requires adverbs not adjectives.