题目

完形填空阅读下面的短文，掌握其大意，然后从短文后各题所给的A、B、C、D四个选项中，选择最佳选项。It’s not easy to be an astronaut’s son. Everybody expects you to be perfect, but I’m just a fourteen-year-old kid, and I’mnot a special1, too, when it comes to math, geography, music, and baseball.    Well, to be honest, I often dream about being some kind of   2 or doing something special—like savinga child from a burning building. I was daydreaming at school one morning whenmy teacher said there would be a Father’s Day writing competitio如右图，在△ABC中，∠C=90°，AB的垂直平分线MN分别交AC，AB于点D，E． 若∠CBD : ∠DBA =3:1，则∠A为（    ）．    A．18°    B．20°    C．22.5°    D．30°