Тут по своему желанию можно написать либо + либо - вариант, я считаю так:
Twenty years from now...
Computers WON'T BE SOLD for $5.
Housework WILL BE DONE by robots
Smells WILL BE INCLUDED in the films and TV shows you watch at home
Hotels WON'T BE BUILT on the moon
All exams WON'T BE TAKEN online
Cars WILL BE POWERED by solar energy
Chinese WON'T BE SPOKEN by everybody in the world.
Wars WON'T BE FOUGHT to get fresh water