Fill in the Blanks Verb to be (ser/estar)Online version Complete the sentences with AM, IS, ARE. by Clara IA 1 'm is am are are is am is isn't are 's are My sister collecting shells . I Clara . I a teacher . My students really nice . You my universe ! Are they swimming in the sea ? What you doing ? We listening to music . What she doing ? She snorkelling . Is she fishing ? Yes , she . Are you playing the guitar ? No , I not . Is he making a sandcastle ? No , he .