单选题The newest fiber-optic cables that carry telephone calls cross-country are made of glass so ______ that a piece 100 miles thick is clearer than a standard windowpane.A fragileB immaculateC iridescentD tangibleE transparent
题目
单选题
The newest fiber-optic cables that carry telephone calls cross-country are made of glass so ______ that a piece 100 miles thick is clearer than a standard windowpane.
A
fragile
B
immaculate
C
iridescent
D
tangible
E
transparent