单选题 Before play-offs, a certain team had won 80 percent of its games. After play-offs, what percent of all its games had the team won?
(1)The team competed in 4 play-off games.
(2)The team won all of its play-off games.
(A) 条件(1)充分，但条件(2)不充分．
(B) 条件(2)充分，但条件(1)不充分．
(C) 条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．
(D) 条件(1)充分，条件(2)也充分．
(E) 条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．

【正确答案】 E
【答案解析】[解析] (1)不充分，因为(1)不知道决赛之前该队参加了多少场比赛；(2)同样不知道决赛之前该队参加了多少场比赛；(1)+(2)同理也不充分。