()是指消声器进口端入射声的声功率级与消声器出口端投射声的声功率级之差。
参考答案:传递损失
In our hometown, about 1,500 meters east of my house,_______ an old temple_______ back to the 17th century.
A.stands; dating
B.is standing; dated
C.standing; dated
D.stand; dating
中国现代学前儿童美术教育发展大致分为:工业实用性——自我表现——创造和审美。