Η άσκηση σεισμού και η άσκηση εκκένωσης είναι αύριο.

Because Greek is treating these as two separate noun phrases:

• η άσκηση σεισμού
• η άσκηση εκκένωσης

When two separate things are joined by και, it is very common to repeat the article. In this sentence, repeating η makes it clear that there are two drills.

If you changed the structure, the meaning could shift. For example:

• Η άσκηση σεισμού και εκκένωσης = more like the earthquake-and-evacuation drill, possibly one combined drill

So the repeated article helps show two distinct events/items.

Because after άσκηση, Greek uses the genitive to show what kind of drill it is.

The basic forms are:

• σεισμός = earthquake
• εκκένωση = evacuation

In the sentence, they become:

• σεισμού = of earthquake
• εκκένωσης = of evacuation

So literally, the structure is something like:

• exercise/drill of earthquake
• exercise/drill of evacuation

This is a very normal Greek pattern.

In Modern Greek, είναι is used for both:

• he/she/it is
• they are

So Greek does not change the verb form here the way English does.

You understand it as are from the subject:

• Η άσκηση σεισμού και η άσκηση εκκένωσης = two things

Since the subject is plural in meaning, English translates it as are.

Greek word order is more flexible than English word order. Putting αύριο at the end is completely natural.

This sentence could also be arranged differently, for example:

• Αύριο είναι η άσκηση σεισμού και η άσκηση εκκένωσης
• Η άσκηση σεισμού και η άσκηση εκκένωσης είναι αύριο

Both are correct. The version with αύριο at the end sounds straightforward and neutral. Putting Αύριο first gives a little more emphasis to tomorrow.

Because αύριο here is an adverb, meaning tomorrow.

Adverbs normally do not take an article, so:

• είναι αύριο = is/are tomorrow

If you see το αύριο, that is different: there αύριο is being used more like a noun, often meaning something like the future or tomorrow as a concept.

So in this sentence, no article is needed.

Yes, but it would suggest a different meaning.

• Η άσκηση σεισμού και η άσκηση εκκένωσης = two separate drills
• Η άσκηση σεισμού και εκκένωσης = one drill connected with both earthquake and evacuation

So the original sentence is clearer if the speaker means there is an earthquake drill and there is an evacuation drill.

It is nominative singular feminine.

Why?

• άσκηση is a feminine noun
• it is the subject of the sentence
• subjects are normally in the nominative

So:

• η = feminine singular nominative article
• άσκηση = feminine singular nominative noun

Even though there are two subject phrases together, each individual phrase is singular:

• η άσκηση σεισμού
• η άσκηση εκκένωσης

Together, they make a plural idea.

Not always. Άσκηση is a broad word that can mean:

• exercise
• practice
• drill

The best English translation depends on context.

For example:

• in schoolwork: exercise
• in fitness: exercise
• in emergency/safety situations: drill

So in this sentence, drill is the most natural English choice because the context is earthquake and evacuation.

Yes, very normal.

Repeating άσκηση makes the sentence explicit and easy to understand:

• η άσκηση σεισμού και η άσκηση εκκένωσης

If you only say άσκηση once, Greek may sound like you are describing one drill with two related aspects, not two separate drills.

So the repetition is not awkward. It is actually useful and natural here.

A simple learner-friendly guide is:

• σεισμού ≈ sees-MOO
• εκκένωσης ≈ ek-KE-no-sees
• αύριο ≈ AV-rio

A few useful notes:

• The stress matters a lot in Greek.
• σεισμού is stressed on the last syllable.
• εκκένωσης is stressed on κέ.
• αύριο is stressed on αύ.

Also, the double κκ in εκκένωσης is mostly a spelling fact in Modern Greek; learners usually do not need to make it dramatically longer.