問題詳情
I mean, if you think of a city like Beijing, for example, public transport is __________. People travel by it. Why? Because it's __________. . It has to be __________. , because there's such a vast number of people.
(A) available
(B) free
(C) possible
(D) unavailable
參考答案
答案：A
難度：適中0.631718
統計：A(717),B(188),C(129),D(101),E(0)