Oh, when was ___ exactly? — It was in

Many countries,America, Japan, Brazil and Spain want to host the 2016 Olympic Games. [ ]

Most scientists seem to agree that ________ certain limit should be set on ______sale of cars to ease air pollution.

The article is ________ more difficult than that one, so I think I can understand it with the help of a dictionary.

Are two students enough to help you carry the desk?— No, the desk is too heavy. I need ______ two.