They are waiting -----.A at the doctor B at the doctor's C.

They are waiting -----.A at the doctor B at the doctor's C. They were waiting ____.A on the doctor's B at the doctor's C They were waiting ___.A.on the doctor's B.at the doctor's C. They are waiting_______.A.at the doctor B.at the doctor's C. They are at the doctor's 对at the doctor's提问. They are (at the doctor's).括号部分提问 they are waiting outside the ( )office.A,doctor's B,doctors there are many people--------- waiting at the doctor's 改成复合句 They were at the doctor's yesterday morning.at the doctor's对 at the doctor、at the doctor’s 、in the doctor 、 in the doctor at the doctor's造句 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