Is this sentence correct?
Today my teacher gave me a sentence goes like this :
Frequently checking cellphones render them less efficient at work.

My question is, frequently here is adverb. so it should be followed with a verb. but checking is a ing form verb which should be considered as a noun. so why not use a adjective to describe " checking "?

Question

Is this sentence correct?
Today my teacher gave me a sentence goes like this :
Frequently checking cellphones render them less efficient at work.

My question is, frequently here is adverb. so it should be followed with a verb. but checking is a ing form verb which should be considered as a noun. so why not use a adjective to describe " checking "?

Answer

A little tricky. 
You are right in saying that "checking" here is acting as a noun. Simplifying the sentence gives us "Checking renders them less efficient at work." (As a side note, it should be "renders" with an "s" for the singular, since the act of checking is a singular noun.)
However, it is not just "checking" but *frequently* checking, and not just checking, but checking *cellphones* - so "frequently checking cellphones" becomes an entire "phrasal noun." (This is not the actual definition of a phrasal noun, but let's just use it for now to describe this phenomenon of a group of words acting together as one noun.) 
In other words, *within* the phrase "frequently checking cellphones," "checking" acts a verb and therefore is modified by an adverb. 
However, the entire phrase "frequently checking cellphones" acts here in this sentence as a noun.

Answer

A gerund has both noun and verb characteristics.

"frequently checking cellphones" = gerund phrase, subject of the sentence.

frequently = adverb for the gerund "checking"
checking = gerund of "to check"
cellphones = gerund object, direct object of the gerund "checking"

Answer

@Jocob. very good example. learned

Answer

It’s correct.
Look at this.
Quickly cooking the food
Quick cooking of the food

Answer

Checking in this sentence is a verb so there is not need to describe it wth an adjective.

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