─ Look, Stella is there!─ That ______ be her. She doesn’t like singing.

______ leaves the room last ought to make sure that the windows are closed and the door locked.

He put up a map ___ the back wall because there was a hole ___ it. [ ]

our earth, or else it will be no longer fit for us to live on.

Which do you like , summer or winter?—I prefer summer.