从A---G选项中选出能填入空白处的最佳选项，补全对话（有两项多余）。

（A man wants to buy a ticket at the station. M is for man. A is for assistant.）

A: Good morning! Can I help you, sir?

M:   小题1:    Could you tell me the time of the last train to Beijing this evening?

A: There’s one at 8:30. But I’m afraid all the tickets have been booked already.

M:   小题2:  

A: The first train leaves at 9:15.

M:   小题3:  

A: It arrives at 12:30. But may be a little late because of the bad weather.

M: OK!  小题4: 

A: Eighty yuan and half of it for a child below 12.

M: 小题5: I’d like two tickets and another one for a child at the age of ten, Here is the money.

A: Thank you!

疲劳裂纹和应力腐蚀裂纹是在（）过程中产生。

A.冶炼

B.锻造

C.机械加工

D.在役使用