新概念英语二的问题~

题目

新概念英语二的问题~
1.It's half 【 】twelve,he still hasn't come.
2.I will not believe it 【 】I see it with my own eyes.
3.He will come back 【 】a minute.
以上三个都是填介词,应该填什么?

答案

1.past
2.unless
3.in