who
- Who’s knocking at the door?—Maybe wanting to sell some new products.
- ______ leaves the room last ought to make sure that the windows are closed and the door locked.
- _____is it? — It’s twelve. [ ]
- I didn’t know __________. Can you tell me?
- ______did you see in the picture?—Nothing.[ ]
- Sometimes I feel stressed, but I don’t know ______for help.