1.stammer vi. 口吃，结巴 vt. 结结巴巴地说 n. 结巴，口吃

He stammers when he feels nervous.
他一紧张就结巴。

2.startled['stɑ:tld] adj. 震惊的，受惊吓的

He had a startled look on his face.
他一脸吃惊的神情。

3.prim[prim] adj. 规规矩矩的，呆板的，拘谨的 vt. 使一本正经，使整洁

You can't tell that joke to her she's much too prim and proper.
可别给她讲那样的笑话--她这人过於古板和认真。

4.sober adj. 清醒的，沉着冷静的，稳重的，颜色暗淡的 vt. 使清醒，使沉着 vi. 清醒，冷静下来

Please sober down a bit; I've got some important news for you.
请严肃点，我有重要消息要告诉你们。