【单选题】In the late 1960s many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized: Ecologists pointed out that a cluster of ta...
A.
compare skyscraper's with other modern structures
B.
describe skyscrapers and their effect on the environment
C.
advocate the use of masonry in the construction of skyscrapers
D.
illustrate some architectural designs of skyscrapers