In my experience working with students to prepare for English-level exams such as TOEFL or IELTS, the testing examiners are not just looking for big words or complex sentences. Yes, they will look to see if you use only basic sentences and your choice of words. They are more interested in how well you express your thoughts and ideas and how you support your ideas throughout the writing. Advanced vocabulary is only good if it is used properly and in the correct context. I would recommend that you focus on writing using words and sentences that you feel are appropriate, not trying to guess what they are wanting and maybe not showing your true abilities.

In Brazil, the people are very happy and like to the party. Carnival is a traditional party, but it is not just samba that people like at Carnival, there are many other types of rhythms as well. For example "frevo" and "baiana" music are also very popular. It is important to remember the structure of English sentences to avoid long run-on sentences. I usually tell my students to plan on a typical English sentence being between 5 to 10 words. There can be exceptions, but it gets more difficult to understand when the sentences go on and on. I suggest that you read the sentences out loud. Whenever you need to pause or take a breath, it is usually a natural place in a sentence to use either a comma or a period. Also in English, the articles (and, the, is, etc) play an important role in the structure and understanding of the sentence. If they are omitted or used incorrectly, it can make it difficult to follow the intent of the information that is being shared.

Duly is not a commonly used word in today's society, but it represents an action that occurs after a certain period of time. For example, I used my new oven for the first time and I was duly impressed. The word duly can refer to someone's actions or to the processing of legal documents, responsibilties, procedures, etc. Today it would be more common to use synonyms like properly, correctly, appropriately, etc in place of the word duly.