"This is an apple."

Translation: Это яблоко.

[salamista]

Is the hyphen necessary?

[hyperion86]

What is the difference exactly between это and этот?

[Berniebud]

"Этот" is for masculine nouns. "Это" can be either for neuter nouns or as a predicate "This is".

"Эта" is for feminine nouns, and "Эти" for plural.

[NoobLucas]

The explanation of what Berniebud said, should you need it:
http://www.russianforeveryone.com/Rufe/Lessons/Course1/Grammar/GramUnit6/GramUnit6_3.htm

[NikolausEn]

The difference between Яблоки and яблоко?

[Kundoo]

Яблоки = apples

[JoshuaKnic]

It's a bit more complicated than that, though you are correct in this case. Яблоки = apples in this case, but in certain forms (like the genetive, I think) яблоки = apple.

[bnDo12]

What is the difference between It and This?

[Siggi967519]

how do i find the russian alphabet? thanks for your help!