Although the most common word for “at” in Russian is «в» followed by the prepositional case, there is a set of very common nouns that use «на» followed by the prepositional case. Among the most common phrases are:

Learning the на words is not all that difficult: by my count there are fewer than a hundred. You can take a look at my most recent list here.

На can also be translated as “on”:

The most common word for “at” in Russian is в followed by the prepositional case:

But в can often be translated as “in”:

If you are an English speaker, your intuition will be a good guide as to when to translate в as in and when as at. Pity the poor Russian speaker, though, who has to figure out the difference in English.

В can also be used to indicate emotional states:

The word потом can be translated several ways, the first of which is with the word then:

The phrase «а потом?» means “and after that?” or “and then?” It sometimes triggers a rhyming response «суп с котом» “cat soup.” It's a response without a specific meaning. It doesn't mean anything bad will happen. It doesn't mean anything good will happen. It is just thrown in when the speaker is having a cuteness seizure. Or when the speaker doesn't want to be more specific because he is irritated or is being coy or wants to tease the listener.

For our foreign readers I should say “a big blue hen” is not a standard English phrase. I simply made up something to rhyme with “and then” to catch the rhyming quality of the Russian phrase.

The word долго means “for a long time,” but it's not the same as давно. Now here is a subtle bit. If an activity has been going on for a long time, but you don't really think of it in terms of starting “a long time ago,” then you use долго instead of давно:

Some people will sloppily translate a sentence like «Мы долго ехали из Москвы во Владивосток» word for word as “We were riding from Moscow to Vladivostok for a long time,” but it's better to paraphrase the sentence thus: “It took a long time to go from Moscow to Vladivostok.” Other examples:

It's possible to find долго and давно in similar-looking past tense sentences, but their meanings are quite distinct:

Russian-speaking Americans often confuse the words давно and долго. Today we will deal with the former. The first meaning of давно is something like “a long time ago.” In this sense it sometimes becomes давным-давно, meaning “a very long time ago”:

Давно is sometimes also translated as “for a long time” in certain senses, but there is a quirk in translating verb tenses between English and Russian with that sense. If you are talking about an activity that still goes on, and that activity began a long time ago, then in English you will often use the present perfect progressive tense, and the equivalent Russian sentence is put in the present tense and uses the phrase давно:

For some verbs you will see the present perfect (see note) instead of present perfect progressive:

If you are talking about something you have NOT done for a long time, then the English sentence is only in the present perfect, and the equivalent Russian sentence shows up in the past tense:

Note: which verbs require present perfect progressive and which verbs require present perfect in English contexts is a complex issue. Stative verbs and dynamic verbs behave differently. The difference between the two is the stuff of which doctorates are made.

Second note: American English is losing the distinction between the past tense and the present perfect. Similarly there is not always a clear distinction between present perfect and present perfect progressive. This is one of the reasons that English is so frustrating to learn. That, and when to use “the,” “a” or no article.