The air in Xuzhou is much worse than that in many other cities.We must do______to protect our environment.
---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?