题目

When Kate heard the news that she won the English speech competition, she was very__________.A.tired B.upset C.serious D.excited 答案：【答案】D【解析】句意：当Kate听到她赢得英语演讲比赛的消息时，她非常激动。考查形容词辨析。tired 累的；upset 沮丧的；serious 严重的；excited 兴奋的。根据句意和常识，赢得比赛，心情是非常激动开心的。故选D。已知直线y=x+1与曲线y=ln（x+a）相切，则a的值为    ．