They ran out of oil.

Question

They ran out of food.
They ran out of rice.
They ran out of money.
They ran out of pens.
He ran out of paper.
He ran out of grocery.
The food is running out.
The oil is running out.
The rice is running out.
His money is running out.

(Are they all grammatical? By the way, what is the meaning of 'out' in the sentences?)

Answer 1

He ran out of groceries. (It is plural).

Answer 2

To "run out" is an idiom that means to be completely gone. The words have to be considered together.

http://www.idiomsite.com/#r

Answer 3

Here's another website that explains "phrasal verbs" -- that is verbal phrases whose words always go together to produce a particular meaning:
http://www.eslcafe.com/pv/
from http://www.eslcafe.com/ >> Stuff for Students