One of the most fascinating things about Russian is its ability to add prefixes to verbs and nouns to give new meanings. For instance, the suffix до- can add the idea of ‘all the way to the end.’ If you add it to читать ‘to read,’ it forms a new verb дочитать ‘to read all the way to the end.’ Normally when you add a prefix to a simple, unprefixed imperfective verb, the new verb is perfective. Then to get an imperfective from the new verb, you add a suffix. In this case the suffix is -ыв-, which gives us the imperfective verb дочитывать. We call this type of verb a derived imperfective. Here is how it is conjugated.

This verb pair is used when you want to specify that you have completed reading something.

Sometimes the phrase «до конца» ‘to the end’ is added to the sentence. That may seem superfluous to the reader, but where is there a rule that says we can't say something more than one way or find another way to say it?

The verb doesn't have to mean that you get all the way to the end of the item, though. It can mean you get all the through to a certain point.

Be careful on that last one. It means that Pasha read chapter four but hasn't yet read chapter five.

The careful reader will remember that прочитать means ‘to read through.’ So what's the difference between прочитать and дочитать? Sometimes not much.

Before we leave this topic, I just want to mention how amazingly common this use of the prefix is. Here are some other examples.

Pretty neat, huh?