+0
Sir,

Last night, all day, every day

these are adverbs or adverbial or adver phrase.

such as

1.I like to play all day.

2.Last night, I could not sleep.

3.I go to school every day.

Thanks.
+0
Terminology always get me down, too. Here's something you may find interesting:

The word "adverb" is a noun, and if we add -al to it we get "adverbial", which is an adjective. If we add -al to the noun "adjective", we get "adjectival".

"adverb" and "adverbial" are the same thing. Use the adjectival form "adverbial" to modify a noun, like this,

adverbial phrase
adverbial clause
adverbial structure

To get to your question:

1. "all day" tells us WHEN I like to play, so it functions as an adverb. It's made of up the adjective 'all' and the noun 'day'. Together, those two words 'all' and 'day' form a phrase. and since that phrase functions as an adverb, it's called an adverbial phrase.

2. "Last night" tells us WHEN, so it functions as an adverb. The two words 'Last' and 'night' form an phrase, an adverbial phrase.

3. "every (single) day" tells us WHEN, so it functions as an adverb. The two words 'every' and 'day' form a phrase, an adverbial phrase.
Comments  
I think they are adverbials.

'An adverbial is a group of words that functions in the same way as an Adverb. '

But do we have adverb phrase this expression? I don't think so.

But I also want to know, if adverbials can work with 'be'? It seems they can, eg.
'-Where's the book?
-It's on the desk.'

Be+ adverbials (which functions in the same way as an adverb) sounds weird to me. I just don't get it. I hope you super-moderators or other experts will help me out too.

Sorry, Hanuman, I hope I didn't ruin your thread.
 Casi's reply was promoted to an answer.