If you are free to walk through out city, please ________ us.A drop in B drop in at C. drop in on
---How is this kind of hamburger? ---It tastes ______ and sells ______.
They go to school __________6:40 _________ Monday morning.
Please give ________ a glass of milk.
What do you usually have ________ lunch?
Do you want _________ an iPad for your birthday?