21. If you want to know the repairs of main engine, which one of following sentences is the better choice?
(A) How is the main engine now?
(B) How is it going?
(C) Excuse me, are you the engineer?
(D) Can I give you some advice?

答案：登入後查看
統計： A(99), B(36), C(29), D(11), E(0) #2335077