例句：
1、Sound travels better in water than in air.
聲音在水中比在空氣中傳播得快。
2、She looked round at the sound of his voice.
聽到他的'聲音，她扭頭看了看。
3、This gives the design team a sound basis for their work.
這為設計組開展工作提供了堅實的基礎。
4、The first year provides students with a sound theoretical basis for later study.
第一年為學生以後的學習奠定堅實的理論基礎。
5、They had a wonderful time by the sound of it.
聽起來他們好像過得很愉快。