Recently people have made great progress in using ____ power of nature to produce____ electricity.
By 16:30, ______was almost closing time, nearly all the paintings had been sold.
We look forward to the day when the motorcar has been replaced by some less dangerous ______of transport.
It took him a long time to ______the skills he needed to become a professional artist.
I’m so glad you’ve come here to ______this matter in person.