不定冠词有a和 an 两种形式,a 用于辅音（不是辅音字母）开头的词前， an 用于元音（不是元音字母）开头的词前。例女口：a boy,a man,a monkey,a university ,a European country; an apple,an egg, an elephant , an old woman , an hour, an honor, an island, anelephant, an umbrella_ pen _ bag _ apple _ monkey _ elephant_ girl _ big apple _ orange banana _ orange pen_ ruler _ old book _ hour _ house_ umbrella Is itThis is Mary isThis isThis isThat isChinese book orring, and it isEnglish book?orange ring.Chinese teacher.English teacher. Tom isbook. It stelephone number.old book.ID card.set of keys. 1 lost my keys. It s It sThis isapple, notpear.orange.peach. ThatsYou have _ banana, but I have _egg. Is there _ umbrella on the desk? There is _ island in the sea.There is _ picture on the card. I have _ old book. _ apple isa kind of fruit.There is _ armchair in the living room. I d like _ egg. Look, there is _ bird in the tree. Is there _ map on the wall?There is _ bench in the park.1. I am_ (a, an)student.2. There is _(a, an) elephant in the zoo.3. You are _(a, an) good boy.4. I have _ (a, an) orange.is _ (a, an) good studento6. Miss Grant is _( a, an )ugly teacher.6. This is_(a ,an)new book.7. Please take _ (a, an )umbrella.8. Close _ (a, an ,the)door, please.9. My father is _ (a ,an) doctor.10. There is _ (a, an) orange on the table.