Possessive 即顯示一種擁有權 (誰的),有possessive noun (this is my parents’ dog 這是我父母的狗), possessive pronoun (the dog is theirs這隻狗是他們的), possessive adj (this is their dog 這是他們的狗)
Present perfect係已終結(沒有延續),如i have finished my work 我已做完
Present perfect continuous 係已完+未完(即你講嘅從以前延續到現在) ,如i have been living in Hong Kong for 40 years 已住40年,會繼續住