They are at the doctor's中的at the doctor's如果是就医的意思,at是动词吗?为什么不用加ing?再对at the doctor's提问.

They are at the bus They are at the airport是什么意思 why are they at the bus stop? why are they at the bus stpp? They are very suprised at the news.为什么用at? things are really different from the way they are at They are _ the woods.They are _ the woods. A.in B.on C.at they are ____koocking at the back doorthey are ____koocking at the back door(尝试) They are (at the doctor's).括号部分提问 look at the insect.what are they?改错 look at the picture and write down what they are they are working at the moment.(改为一般疑问句） Look at the ___(four)boys.They are my brothers. They are sleeping at the moment.(划线部分提问) at this moment,they are cleaning the classroom错那 They are waiting for you at the library是什么意思 Look at the red maple l____.They are very beautiful. Look at the [man] .They are eating dinner.