The Right answer is Dominican Republic
Well, I can't completely help, but I do know some tricks.
For example, write it out fully in English, or the best language you have fluently, then put the whole essay into a translator. Next, make a new document, and copy and paste the translated version into it. Read it out many times, get some quick help (I know some podcasts that can help you learn Spanish easier, like Duolingo) and, once you have learned a bit more (another trick is to read through it using the translator, and see some of the translation parts to learn more Spanish from words that you used) filter out any kinks, and turn it in! It seems harder written out than it is, but it's an efficient way!
Answer:
How about saying this instead:
Mi hermano tiene diecinueve años y creo que es perezoso y aburrido.
Explanation:
Manuel visitó a sus primos en Venezuela.
Blanca y Virginia tomaron cursos en la universidad.
Tú viajaste con tu familia.
Alex y yo cantamos el coro.
Yo comencé a estudiar el violín.
Efraín jugó en un equipo de béisbol.