2nacionalidades rewrite the sentences using adjectives of nationality.
modelo emiliano es de italia. es italiano.
olivia es de argentina. el profesor es de alemania. carlos y yo somos de canadá. la turista es de costa rica. los ingenieros son de españa. margaret y anne son de inglaterra.

The resulting sentences are listed below:

In this question, we must derive the nationality associated to the country indicated in the original sentence. The grammatical constructions of the original and the resulting sentences are presented herein:

Original sentence

Subject + verb "ser" + de + country

Resulting sentence

Subject + verb "ser" + nationality

Now we proceed to present the entire solution:

1) Olivia es de Argentina. Olivia es argentina.

2) El profesor es de Alemania. El profesor es alemán.

3) Carlos y yo somos de Canadá. Carlos y yo somos canadienses.

4) La turista es de Costa Rica. La turista es costarricense.

5) Los ingenieros son de España. Los ingenieros son españoles.

6) Margaret y Anne son de Inglaterra. Margaret y Anne son inglesas.  

We kindly invite to check this question on sentences in Spanish: link

The correct answers for:

Olivia es de Argentina. Ella es argentina (she is argentinian here the country doesn't change.)

El profesor es de Alemania. Es Alemán ( He is German in this case the word does changes.)

Carlos y yo somos de Canadá. Somos Canadienses (We are canadians, look how ienses changes in this time, it is not the rule for all the countries.)

La turista es de Costa Rica. Es costarisense

Los ingenieros son de España. Son Españoles

Margaret y Anne son de Inglaterra. Son ingléses.

Explanation:

All right to understand why sometimes the whole structure changes and why sometimes it doesn't let's see this:

First of all, almost all nationalities are predetermined by sex male/woman in Spanish. So the nationalities that end in "O" termination for men "a" for women. If it's plural we only add an "s" to specify there is more than one subject.

The nationalities that end in "se" like Canadiense, Costarisense, Estado Unidense (American) don't have sexual termination, they are the same for both sexes. To write plural is the same as the above ones, you just add an "s".

The nationalities that end in Í stay the same for both sexes and add an "s" for plural. Marroquí Moroccan.

The nationalities that end in consonant follow the sex rule: Inglés, Inglesa. English. And plural "s" addition.

You have to be very very careful because this is a very difficult topic. But if you practice it there won't be any problem. They also don't require a capital letter at the beginning of the word.