1·The steam whistle is blowing.
汽笛在叫。
—— 《新英汉大辞典》
2·The continuity of a steam whistle is due to the intense rapidity of its sequential "explosions".
汽笛的连续性，是由于它的连续“爆炸”的强烈速度。
3·The sound of a steam whistle fell upon a wilderness. At the parting moment immeasurable melancholy and loneliness welled up in my mind.
一声汽笛，跌落在旷野，无限的惆怅与孤独在离别的那一刻，一起涌上心头。
4·But at last he got to like trains, because when he heard steam whistle, instead of remembering the unhappy, he thought of the excitement and the waving hands of the tourists.
不过后来他喜欢上了火车，因为当听到汽笛声，他不再想到不愉快，而是想起每次看火车时的兴奋，以及旅客挥舞的手。