----- Nội dung dịch tự động từ ảnh -----
Read the following passage and mark the letter A, B, C or D to indicate the orrect answer to
each of the questions.
and
In the twentieth century, architects in large cities designed structures a way that reduced
noise and yet made living as comfortable as possible. They used such techniques as making walls
hollow and filling this all space with materials that absorb noise. Thick carpets and heavy
curtains were used to cover floors and windows. Air conditioners and furnaces were designed to
filter air throughoundproofing materials. However, after much time and effort had been spent in
making buildings less noisy, it was discovered that people also reacted adversely to the lack of
sound. Now architects are designing structures which reduce undesirable noise but retain the kind
of noise that people seem to need.
28. The word "they" refers to
A. architects
EM
B. cities
C. structures
D. techniques