Later in this chapter cases will be introduced to readers ____ consumer complaints haveresulted in changes in the law[ ]

you read, you understand.

(2014·江西红色六校高三第二次联考)—How did you pass the challenging test?—It was a long time________I found a series of suitable methods

The maths problem was so difficult thatnone of us could ____.

________? —–I think China is a great country with friendly people and a long history.