They are trying to find a new way to __________ the spread of AIDS.
The suggestion he _______ is that all the students ______ the orphan.
What the expert has said and done will be _________ to the department manager.
---Is Peter in the office, talking with your manager? --- Yes, but I would rather he ___________ yesterday.
Should the present unemployment continue, the society________a more troublesome situation.
He would have gone to visit Linda yesterday, however , he _____on by Linda instead.