1. She used to underline favorite passages to share with her husband.
    过去，她常常在她喜欢的段落下面划上横线，以便让丈夫一道欣赏。

2. But they do underline the general principle that the relationship between elephant and mahout is the key to successful training.
    但强调了一项基本原则，象和驯象员之间的关系是驯象成功与否的关健。