When you are sleeping, you had better _____ all your windows closed. [ ]

It is useful to be able to predict the extent _____ a price change willaffect supply and demand.

__________ did your uncle leave his hometown ? He _________ for nearly 20years .

Martin has been working hard and comes top in the class.— It is his mother’s love that helps him feel good about .

What do you think of the 3D film Titanic last night?– It was _________. I enjoyed it a lot.