Яз (fill in a/an or some . then mark the nouns as c(countable) or u(uncountable)) egg // rice // cheese // discuit//.

"Яз" (fill in a/an or some . then mark the nouns as c(countable) or u(uncountable)) egg // rice // cheese // biscuit//.

Example answer:

To fill in the gaps and determine whether to use "a/an" or "some", we need to understand whether the given nouns are countable or uncountable.

1. egg - countable noun: Since "egg" refers to one unit, we use "an" before it. So, the correct answer is "an egg".

2. rice - uncountable noun: "Rice" is a substance that cannot be counted individually. We use "some" before uncountable nouns. So, the correct answer is "some rice".

3. cheese - uncountable noun: Similar to "rice", "cheese" is not counted individually. We use "some" before uncountable nouns. So, the correct answer is "some cheese".

4. biscuit - countable noun: "Biscuit" refers to one unit, so we use "a" before it. The correct answer is "a biscuit".

Final sentence:
"Яз an egg // some rice // some cheese // a biscuit."
(Яз яиц // немного риса // немного сыра // бисквит).