To complete the first dialogue, we need to understand what is being said in order to supply the right response.

By this point, you should be relatively comfortable reading a sentence of this level of complexity, but if you’re having trouble, a good strategy is to look for particles to see how each word in the sentence functions. Just remember that some words do not take particles and that some particles can function in multiple ways. Another important thing to remember to increase your reading comprehension is that Japanese sentences always end in verbs. These pieces of information should give you a good chance at figuring out what is going on in a simple Japanese sentence.

In the first line of the dialogue, A tells B that they are not going to class tomorrow. B responds by asking why. This is the question to which we need to respond.

Using the vocabulary that we already know, we can easily say that tomorrow is a holiday, though feel free to supply your own solution. To say that one thing is another thing, we use the ‘XはYです’ construction. To make it into a reason, we simply append ‘から’ to the end of the sentence.

Even though ‘tomorrow’ typically does not take a particle, we will mark it with ‘は’ here to make our explanation clearer.

Once we know what we want to say and how we want to say it, we can answer as follows:
明日は休みですから。（あしたはやすみですから。）

To complete the second dialogue, we need to understand what is being said in order to supply the right response.

The only piece of information we have to go off of here is that, after A says something of our own construction, B asks why that is, to which A answers something else that we get to decide. Thus, we can construct the missing sentences however we want. We’ll have A say that they didn’t eat breakfast this morning because they slept, though feel free to supply your own solution.

We’ll introduce a new word here that you may not be familiar with from your studies in Genki I: ‘今朝（けさ）.’ This word means ‘this morning,’ and it is very commonly used in Japanese.

To say that A didn’t eat breakfast this morning, we will use a standard verb-sentence construction. In this sentence, there will be a topic, a non-specific time word (a word that does not refer to an unchanging date), a direct object, and a verb conjugated into the negative past form.

To say that A slept, with the implication that this is the reason for them not eating breakfast, we simply need to use the verb for ‘to sleep’ in the past form. Once we have conjugated that, we can append the conjunctive particle ‘から.’

Once we know what we want to say and how we want to say it, we can answer as follows:
今朝、朝ご飯を食べませんでした。（けさ、あさごはんを食べませんでした。）
寝ましたから。（ねましたから。）