最佳选项。

B

    I work as a volunteer for the poor in Haiti. I decided to take my son Brain there for a week, hoping to educate(教育) him.

    Before getting out, I told Brain this trip would be tiring and hard. For the first two days, he said almost nothing. Then on the third day, when we were climbing over high rocky mountains, he turned to me and smiled, "Really hard."

    After that, a five-year-old girl, wearing a too large dress and broken shoes, followed Brain around. Later he said regretfully(遗憾地), "I wish I could speak French." I was surprised that this was from a boy. He always hated French classes.

    One day, I was interviewing(采访) a woman villager for an article. By working hard, she had learned to read and write and became part of the leadership(领导层) of the village. That really touched my heart.

    Learning her story, Brain was greatly touched. His eyes were wet and there was love and respect(尊重) on his face. He finally understood the importance of my work. When leaving for home, Brain even offered(提供) to stay in as a volunteer. This trip was very meaningful.

若函数e^xf（x）（e=2.71828…是自然对数的底数）在f（x）的定义域上单调递增，则称f（x）具有M性质，下列函数中具有M性质的是（　　）

补写出下列句子中空缺的部分。

①《烛之武退秦师》中说出了晋国秦国联合围攻郑国的理由是：____，____。

②《荆轲刺秦王》中，易水诀别时，荆轲悲壮的唱词是：“____，____！”

③李白《行路难》（金樽清酒斗十千）一诗经过大段的反复回旋，最后境界顿开，用____，____两句表达了诗人的乐观和自信。