He is really an excellent doctor and he is____to becoming an expert in this field.
We offered these students a summer course, aimed __________ improving their spoken English.
__________ to go to university, we must work hard.
The explorers were told to __________ themselves with everything they would need for the voyage.
The old teacher lay wide awake on his bed, __________ all the problems he had to deal with the next day.
—What kind of party is it? Need we __________? —Yes. It's a very formal occasion.