He allowed me ____ the experiment.
I'm sorry you ______ so long, but it' ll still be some time before Jim gets back.
In college, you will discover ______ learning is about, from teacher-taught to self-learner.
Since the end of the war, many of the priceless antiques ______ to their rightful owners.
_______the money shortage, many small companies closed down.
Do you know the thief_______by the police.