单选题 . ①The physicist Wallace Sabine pioneered the scientific study of architectural acoustics when he was asked in 1895 to fix a university lecture hall in which the echo of a speaker's words rendered them unintelligible. ②He found that the length of time it takes a sound's echo to decay is determined by the absorption of the sound's original energy by surrounding material. ③By hanging panels of sound-absorbing felt on the walls, Sabine reduced the echo enough to make the hall usable. ④And the data he compiled yielded a mathematical formula for the relationship between a room's echo duration, its quantity and quality of sound-absorbing materials, and its spatial volume.

19. Which of the following can be inferred about the 'university lecture hall' mentioned in the passage? ______

A、 It was not originally designed to be used for lecture.
B、 It was more suitable for listening to music than for listening to the spoken word.
C、 Its walls had surfaces made of material with very poor sound-absorbing properties.
D、 Its poor acoustics resulted from its being designed to accommodate a large audience.
E、 It was constructed at a time when sound-absorbing building materials were not readily available.

【正确答案】 C

【答案解析】 C：根据文章，既然华莱士·萨宾通过使用吸收声音的材料使得报告厅的回声现象减少，因此可以得知报告厅一开始不具备很好的吸收声音的材料，因此选项C正确。