at time,on time,in time

题目

at time,on time,in time
三者都表示什么?在什么情况下用?

答案

at time:偶尔eg.I would go to climb the mountain near my school at time when at my early age.
on time:准时eg.He appeared at the meeting on time.
in time:及时eg.Luckily,she rushed to the airport in time.