题目：Which of the following is true of English sound system（）
A．Aspiration is a distinctive feature
B．Voicing is a distinctive phonetic feature
C．Nasalization of vowels gives rise to another vowel
D．Length of vowels differentiates one vowel from the other
考查发音系统的区别特征。语音的区别性特征主要包括辅音化、响音、鼻音和浊音。故选B。元音的长短只能区分单元音，并不能区分双元音，所以D项说法不正确；A、C两项也不正确。故选B