on time：按时 ，准时

The bus came right on time. 公共汽车正好准时到达。

The work was finished on time and within budget.工作按时完成且未超出预算。

They are unlikely to get here on time, I fear.恐怕他们不大可能准时到达这里。

in time：及时 ，常含有匆忙之意。

You’re just in time.  你来得正是时候。

I hope we get there in time. 我希望我们及时到达那里。

Did you get your article done in time? 你的论文按时完成了吗？