1. Their flexibility of the tongue and lips is acquired later, and with no small difficulty.
    他们舌和唇的适应性是稍大之后取得的，而且不是一学就会。

2. Learning to tolerate a stranger's habits may teach undergraduates flexibility and the art of compromise, but the learning process is often painful.
    学会容忍陌生人的习惯，可使大学生学会灵活应变和妥协的艺术，但这往往是一个十分痛苦的过程。