Mary wrote an article on ________ the team had failed to win the game.

A．why

B．what

C．who

D．That

“每一个原则在一定时间内都曾经是主导原则，当整个世界皆据此唯一原则来解释时，这就叫做哲学系统。”是（）的名言。

A.马克思

B.恩格斯

C.黑格尔

D.列宁