the cat is under the desk这个句型为什么有is

the cat is under the desk这个句型为什么有is the cat is sleeping under the desk My cat is (under the desk).(划线提问) What is under the desk? there is a ball under the desk. these is a cat on the什么意思? The girl under the desk is Lucy The footboll is under the teachers' desk. 根据答句写出问句 ____________--His cat is under the desk ________ -Y under the it desk is怎么排列 Is (they) football under the desk? There is a cat under the chair. 句型转换-英语 There is a cat under the tree（对画线部分提问）