I used this song to practice / get students to notice how subject, object and possessive pronouns are used in English as some struggle with she / her and he / him in subject-verb-object. There are also examples of reflexive pronouns which clearly show how and why we use them. You can also modify it to use for teaching articles as there are heaps of examples of when to use "the" and "a/an" (definite and indefinite articles). It can also be used as a pre-activity before you introduce the grammar (of pronouns). Marker sentences can be plucked from the lyrics to teach this language point. Also, it's a good song, they speak/sing clearly, there are heaps of vocab you can teach them as well. My students really liked this one.
