27.If you ________ to something different, for example to a different system, task, or subject of conversation, you change to it from what you were doing or saying before.
The scientists predict that if present trends______, women in 400 years will be 2cm shorter and have healthier hearts.
Bush, before Barack Obama, _______ Brown a similar gift, a leather bomber jacket.
The students _____ busily when Miss Brown went to get a book she ____ in the office.
With the world changing fast, we have something new ______with all by ourselves every day.
The discussion was held in a lively______ with members talking freely to each other.