問題詳情
6. Solar energy production has made huge strides in recent years, _______ advances in photovoltaic technologies the underpinnings of solar panels have made it easier and cheaper to harness energy from the sun.
(A) despite
(B) unless
(C) while
(D) as
參考答案
答案：D
統計：A:1,B:0,C:1,D:5,E:0
難度：計算中