The Russian word for tea is чай. It declines like this:

You don't usually find the plural forms, but occasionally they are used to mean ‘types of tea.’ Mostly you just use the singular.

Tea always reminds me of a classic English joke. Supposedly between Lady Astor and Winston Churchill there was constant verbal sparring:

If you want to ask how often something happens in Russian, you can use the phrase «как часто»:

Now here's one of those subtle differences that occur between languages. Although the «как часто» phrase is perfectly grammatical in both Russian and English, the frequency of the use of the phrase is not the same. The English phrase is much more common in usage. In Russian it is more common to ask the question slightly differently, phrasing it simply "Do you often?":

When you ask the question, it is usually used with intonation construction three, jumping up on the stressed syllable of часто:

The adverb часто means frequently. Since it tells how often something happens, we can more specifically call it an adverb of frequency. It's often used much the same way as its English equivalent:

Часто is what we call the the "positive form" of the adverb; adverbs often have a "comparative form" as well, and in this case that form is чаще.

You may remember from yesterday that the case forms of год are:

Today we need to discuss the genitive singular forms. The modern version of the genitive singular is года, but there is an older form that arose as a consequence of the u-stem genitives which nowadays only appears in stock phrases. So you will occasionally find phrases like:

For instance:

There is a tendency in language to make the things that are irregular more regular. Thus the older plural ‘brethren’ in English has been mostly replaced by ‘brothers.’ Similarly nowadays it is much more common in Russian to say «год от года» than «год от году». It is still more common to find «без году неделя» than «без года неделя», but that ratio will most likely eventually change in favor of года.

Language changes. For instance, as I was growing up, I never heard anyone say “You want to come with?” for “Do you want to come with us?” I remember the first time I heard it. I thought “No native speaker of English could possibly ever say that!” I was wrong. All sorts of US native speakers say it nowadays, and nowadays it almost doesn't sound strange to me. This should teach us a lesson. No native speaker ever knows the entirety of his language. And if we find that Russian speakers occasionally give us contradictory language about their native language, this is also normal. In such situations, you need to ask multiple native speakers about your language issue, and then draw a rule of thumb from their responses.

The case forms of год are:

Note the two nominative plural forms. Dictionaries list both, but truth to tell you almost never see the года version for the plural.

Note the two forms for the genitive plural. The form лет is used after numbers and а few other words like много, мало, сколько and несколько. Годов is used everywhere else:

Note the two forms of the prepositional case. The form in -у is used to say "in such and such a year", and the -е form is used as the prepositional case form in other contexts:

We will address the alternative genitive forms tomorrow.