I found ______difficult to choose one colour among them.
-- I don’t know ______ with this problem. It’s too hard. --- You can ask Mr Wang for help.
I used to go to sleep ________ my bedroom light ________.
—There is ____ time. You don’t need to hurry. —But I want to see her as early as possible.
There are ________ students waiting in the hall, ________?
You should keep the window _________ because the room is so hot and damp.