What verbal phrase that can be used as a noun adverb or adjective and is preceded by the word a?

The verbal phrase that can be used as a noun, adverb, or adjective and is preceded by the word "a" is "while".

Here's how it works:

* Noun: "A while" can refer to a period of time.

* Example: "I'll be back in a while."

* Adverb: "A while" can modify a verb, adjective, or another adverb, indicating duration.

* Example: "Wait a while." (modifies the verb "wait")

* Adjective: "A while" can describe a noun, indicating a period of time.

* Example: "A while ago, I saw a bird." (modifies the noun "ago")

Let me know if you'd like to explore other verbal phrases or grammatical concepts!