Questão 1013381

Without proper grammar, written or spoken words usually lose their exact meaning and much of their value as well. […] However, the task becomes much tough to teach in an ESL setting.

One common way is to focus _____ the different forms and rules and helping students to learn the subject with help of rote memorization.

Disponível em: <http://eslarticle.com/>. Acesso em: 18 fev. 2017.

Qual preposição completa corretamente o texto?