阿摩線上測驗
18. _____ flying, a bat emits a rapid series of ultrasonic signals, which bounce off any object in its
path.
(A) When it is
(B) When it
(C) When is
(D) It is
答案：登入後查看
統計： A(133), B(25), C(5), D(0), E(0) #2856568
統計： A(133), B(25), C(5), D(0), E(0) #2856568
