Explicação com vídeo: https://www.youtube.com/watch?v=tVuVrVr4dvI
Link 1: http://www.language-worksheets.com/support-files/elementarypresentcontinuousexercises.pdf
Link 2: http://www.uhu.es/antonia.dominguez/present.pdf
Link 3: http://www.e-grammar.org/download/present-continuous-positive.pdf
