The first meaning of the preposition на is “on.” In this meaning it is complemented by the prepositional case.

One of the most important and valued items in a Russian’s wardrobe has been the warm, soft and heavy sheepskin/lambskin coat known simply as дублёнка. Russians have always prized this particular garment very highly because it can keep one cozy on cold Russian nights, when the icy, piercing northern winds raise sweeping blizzards. And more importantly... because it costs some serious rubles. But fortunately, once you buy a quality дублёнка, whether it’s out of basic sheepskin, lambskin or the lavish shearling, it can serve you for half a lifetime. When I think of a дублёнка, the first thing that came to my mind is my grandfather’s old, rugged sheepskin coat that he has had since the early seventies and still wears today when out in the snowy countryside. Overall, sheepskin coats remain quite popular with men and women alike.

Image from img11.nnm.ru

A hefty дублёнка worn by Vasily Alibabayevich, a character from the famous Russian comedy "Gentlemen of Fortune."

Here are some example sentences with the word:

Russian has a verb болеть which means “to hurt, ache,” and another verb болеть which means “to be ill.” That's right: their infinitives are spelled exactly the same, although they are conjugated differently. Today we will discuss the former.

The first thing to notice about the verb “to hurt, ache” is that it is only used in the third person, never in the first or second:

In English we say, “My head hurts.” The Russians phrase it as “at me hurts the head”:

There are а couple things to note here. First of all, the person experiencing the pain shows up in the genitive case as the object of the preposition у. The body part that hurts shows up in the nominative case. Since the body part is the subject, the verb has to agree with it, not with the person who is suffering. If more than one thing hurts, the verb goes in the plural. Thus:

The prefix за- often adds the idea of “start to” to a verb, and the perfective заболеть is not an exception. Here are some examples.

Some words always bring a smile to my face, like higgledy-piggledy, hurlyburly, hullabaloo, and floccinaucinihilipilification. Now I have a new one from Russian: гоголь-моголь.

Гоголь-моголь is a dish made of raw egg yolks beaten with sugar. If your daughter has a sore throat and doesn't like to take medicine, then you feed her гоголь-моголь and soon everything will will be better.

Photo courtesy of Wikipedia

Even Doctor Aibolit, the Russian equivalent of Doctor Doolittle, treated his animals with it:

Гоголь-моголь is considered a cultured and refined dessert, worthy of being served in aristocratic homes. It may be flavored with chocolate or vanilla or coffee, made with fruit juices or pureed fruit, or even served in bars as a cocktail.

One interesting and very common use of unchanging это is to refer to a situation broadly. Consider this sentence:

Although «Это были наши соседи» and “It was our neighbors” resemble each other superficially, they are grammatically quite different. In the English sentence “it” is the subject, singular “was” agrees with “it”, and “neighbors” is a predicate noun in the plural. In the Russian sentence соседи is the subject and induces verbal agreement. Notice that это does not agree in gender with anything in the sentence that precedes it. It's not referring to the night. It's not referring to the noise or the neighbors. It refers to the whole, abstract situation. Here are a couple other examples.

This use of unchanging это is not limited to “be” sentences. For instance, in Crime and Punishment Raskolnikov confesses with this phrase:

This use is a bit different than the one we discussed earlier because instead of referring to a whole abstract situation, это serves to direct the listener's focus on the identity of one particular person in the situation:

¹ The precise quote is «Это я убил тогда старуху-чиновницу и сестру ее Лизавету топором и ограбил.» “It was I who killed the old woman and her sister Elizabeth with an axe and robbed them.”