阿摩線上測驗
21. I find it hard to concentrate on studying with the radio ______.
(A) turning on
(B) on
(C) be turned on
(D) to turn on
答案：登入後查看
統計： A(59), B(36), C(22), D(1), E(0) #628420
統計： A(59), B(36), C(22), D(1), E(0) #628420
