Il lavoro è difficile; inoltre, è importante.

Il is the masculine singular definite article, meaning the.

So:

• il = the
• lavoro = work / job

Together, il lavoro means the work or the job, depending on context.

Italian usually uses articles more regularly than English, so where English might sometimes just say work, Italian often says il lavoro.

Lavoro here is a noun, not a verb.

• lavoro = work / job (noun)
• lavoro can also mean I work as a verb form, but not in this sentence

In Il lavoro è difficile, the word after il is clearly being used as a noun, because articles like il normally come before nouns.

Because the sentence contains two separate statements about the same thing:

1. Il lavoro è difficile = the work is difficult
2. è importante = it is important

Italian often leaves out a repeated subject when it is obvious. So in the second part, the subject il lavoro is understood and does not need to be repeated.

You could also say:

• Il lavoro è difficile; inoltre, il lavoro è importante.

But that sounds repetitive. The shorter version is more natural.

Because Italian often omits subject pronouns when the subject is clear from context.

In English, you usually need it is important.
In Italian, once il lavoro has already been mentioned, you can simply say:

• è importante

The listener understands that it means:

• il lavoro è importante

This is a very common feature of Italian.

Inoltre means moreover, furthermore, or in addition.

It is used to add another piece of information, often in a slightly formal or written style.

In this sentence:

• Il lavoro è difficile; inoltre, è importante.
• The work is difficult; moreover, it is important.

So inoltre connects the first idea to an additional second idea.

The semicolon separates two closely related independent statements.

Here, both parts could stand alone:

• Il lavoro è difficile.
• Inoltre, è importante.

Using a semicolon shows that the two ideas are strongly connected.

You may also see:

• Il lavoro è difficile. Inoltre, è importante.
• Il lavoro è difficile, inoltre è importante.

But the semicolon is a neat, clear punctuation choice, especially in more careful writing.

Yes. Italian allows some flexibility.

For example:

• Il lavoro è difficile; inoltre, è importante.
• Il lavoro è difficile; è inoltre importante.
• Inoltre, il lavoro è importante.

All of these are possible, though they may sound slightly different in rhythm or emphasis.

The version in your sentence is very natural and clearly marks inoltre as a connector between the two ideas.

Because they are being used as predicate adjectives: they describe the subject after the verb to be.

Structure:

• Il lavoro = subject
• è = is
• difficile / importante = adjective describing the subject

This is normal in Italian, just as in English:

• The work is difficult
• The work is important

So the pattern is very straightforward.

Yes, adjectives in Italian normally agree in gender and number with the noun they describe.

Here, lavoro is:

• masculine
• singular

So the adjectives must be singular too.

In this case:

• difficile has the same form for masculine and feminine singular
• importante also has the same form for masculine and feminine singular

So even though agreement is happening, you do not see a different ending here.

For the plural, they would change:

• I lavori sono difficili e importanti.

No. This is a very important distinction.

• è with an accent = is
• e without an accent = and

So:

• Il lavoro è difficile = the work is difficult
• Il lavoro è difficile e importante = the work is difficult and important

The accent matters both in writing and meaning.

Yes, absolutely.

That would mean:

• The work is difficult and important

This is a simpler way to connect the two adjectives.

The version with inoltre is a bit different in tone:

• Il lavoro è difficile; inoltre, è importante.

This feels more like:

• first statement: it is difficult
• additional point: besides that, it is important

So both are correct, but inoltre gives a stronger sense of adding a second, separate point.

It is fairly neutral to slightly formal, mainly because of inoltre.

In everyday speech, people might more often say:

• Il lavoro è difficile, ma è importante.
• Il lavoro è difficile ed è anche importante.
• Il lavoro è difficile e importante.

Using inoltre is perfectly correct, but it sounds a bit more polished or written.

Because the second part still needs its own verb.

Even when the subject is omitted, Italian still needs the finite verb:

• Il lavoro è difficile; inoltre, è importante.

You cannot normally remove the second è and say:

• Il lavoro è difficile; inoltre, importante.

That would sound incomplete in standard Italian.

So:

• the subject can be left out because it is understood
• the verb still has to be there

The fully expanded version would be:

• Il lavoro è difficile; inoltre, il lavoro è importante.

This is grammatically correct, but it sounds heavy and repetitive.

Italian prefers to avoid repeating an obvious subject, so the original sentence is more natural:

• Il lavoro è difficile; inoltre, è importante.