根据对话内容及所给首字母提示补全所缺单词,完成对话（含缩略形式）.

根据对话内容及所给首字母提示补全所缺单词,完成对话（含缩略形式）.
A:Excuse me.Are you a v___?B:Yes,I am.What can I do for you,sir?A:Can you tell me w___ we can't go into the training center now?B:Sorry,sir.You need to register at the entrance.And that takes some time.A:I see.It seems that we have to keep on w___.B:I'm sorry about that.But this is necessary.A:But look at such a long line```.B:There are too many people coming into the training center today .I hope you can u___?A:OK.As a volunteer,you're doing what you should do.B:I'm sure it won't take too long.Thank you f___ your understanding.