15. _______ all the inventions have in common is _____they have succeeded.A. What; what B. That; that C. What; that D That; what
One solution to this problem now is sustainable development.
Wind power units are placed ______ there is a lot of wind.
Recently, there a boom in population movements.
______developing countries need to do is to stop poverty.
That's the best way you thought of _______ into dangerous areas.