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"Become" is a copular verb which is often translated as "convertirse en", and "but" is a conjunction which is often translated as "pero". Learn more about the difference between "become" and "but" below.
become(
bi
-
kuhm
)A copular verb links the subject of a clause to the predicate (e.g., My brother is tall).
a. convertirse en 
He became the most influential director on the board.Se convirtió en el director más influyente de la junta.
b. volverse 
He became distant and didn't contact her for nearly a week.Se volvió distante y no la contactó durante casi una semana.
c. hacerse 
After many years of study, he finally became a lawyer.Después de muchos años de estudio, finalmente se hizo abogado.
d. llegar a ser 
There's a chance he could become the country's next prime minister.Es posible que llegue a ser el próximo primer ministro del país.
a. ponerse 
She became sad upon hearing the tragic news.Se puso triste al escuchar las trágicas noticias.
a. convertirse en 
That little striped caterpillar will become a magnificent monarch butterfly.Esa oruga rayada se convertirá en una maravillosa mariposa monarca.
A transitive verb is a verb that requires a direct object (e.g., I bought a book.).
4. (to suit)
a. ser propio de 
That way of speaking does not become a teacher.Esa manera de hablar no es propio de un maestro.
but(
buht
)A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
2. (emphatic)
An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
3. (only)
A preposition is a word that indicates the relationship between a noun and another word (e.g., He ran through the door.).
A noun is a word referring to a person, animal, place, thing, feeling, or idea (e.g., man, dog, house).
5. (objection)