Curated OER
Grammar Games and Activities
Thirty pages of grammar activities? Your young grammarians will be well versed in the parts of speech, basic verb tenses, and much more after completing even a handful of these exercises. 
Other
Isabel's Esl Site: Present Continuous Tense
Focus on the present continuous tense, with explanations, examples, exercises, and comparisons to other forms. Some guidance in Spanish.
Other
Eclectic English: The Present Continuous Tense the Ing Form of Verbs
Learn how to correctly add the -ing ending to various types of words, and then practice by adding -ing to twenty-two verbs.