If it were not for the fact that Anne _______ ill, I would invite her to answer my question now.
What the boy enjoys _____ to have a room of his own.
Which do you enjoy ____ your weekend, swimmingorfishing?
I think this is the very work that we must finish ____ her.
The work he devoted his time to _____ worth praising.
The theory he sticks to ______ to be of no use in our studies.