---I’m sorry but there is no smoking on this flight.---Oh I that. Sorry I won’t again.A

问题补充：

---I’m sorry, but there is no smoking on this flight.

---Oh, I that. Sorry, I won’t again.

A. don’t know

B. didn’t know

C. won’t know

D. haven’t known

答案：

A. don’t know

(答案→)B. didn’t know

C. won’t know

D. haven’t known

解析：考察时态。句义：—对不起。在飞机上不能抽烟。—哦！我之前不知道这点。我以后不会再这样做了。根据句义可以在说话之前不知道在这里禁止抽烟。故使用一般过去时。B正确。