21. Mary: Can you show me how to use the app?
Danny: ______________________.
Mary: It works! Thank you so much for the help.
(A) I don’t need yours.
(B) The app is not cheap.
(C) Here is my phone.
(D) Sure. Why not?

答案：登入後查看
統計： A(0), B(1), C(0), D(1), E(0) #3814446