1 . _________ the precise qualities of a hero in literary words may vary over time, the basic exemplary function of the hero seems to remain constant.

A．Unless

B．Since

C．Whether

D．Even though

2 . ______ I agree with you, I don’t think your solution is the best.

A．If

B．Since

C．While

D．As

3 . ________in everyday life consumers have seen lots of successful examples of advertisements like Kodak, Nike, Coca-Cola, and McDonald’s, there are still some examples that do not reach the expected goal.

A．As

B．Because

C．In addition

D．While