問題詳情
【題組】7. The production of glass fibers wasimproved in the nineteenth century bywhich of the following
(A) Adding silver to the molten glass
(B) Increasing the circumference of theglass tubes
(C) Putting silk thread in the center of thefibers
(D) Using yam reels
參考答案
答案：D
難度：適中0.4
統計：A(0),B(2),C(1),D(2),E(0)