a dog is being petted adog being petted

a dog is being petted adog being petted petted的音标 Is that being a dog.中为什么is和being会同时出现? the dog ___ mad?A:looks B:is looked C:is being looked D:was being a volunteer is great Is that being a cat中为什么要用being --___a volunteer is great.A.Being B.To being is being 和are being Being cool is being popular. being cool is being popular being Being a teacher is a good（）.