例句：
1、Sound travels better in water than in air.
声音在水中比在空气中传播得快。
2、She looked round at the sound of his voice.
听到他的声音，她扭头看了看。
3、This gives the design team a sound basis for their work.
这为设计组开展工作提供了坚实的`基础。
4、The first year provides students with a sound theoretical basis for later study.
第一年为学生以后的学习奠定坚实的理论基础。
5、They had a wonderful time by the sound of it.
听起来他们好像过得很愉快。