It’s an afternoon departure. The flight leaves at 15.20.
下午出港。航班15：20起飞。

A I’m off to Shanghai tomorrow afternoon.
A 我明天下午去上海。

B Of course, I forgot. You’re going to Shanghai, aren’t you?
B 当然，我忘了。你要去上海，不是吗？

A Yes, just for the weekend. I’m back on Monday.
A 是的，只是度个周末，我周一就回来。

B What time’s your flight?
B 你的航班什么时候起飞？

A It’s an afternoon departure. The flight leaves at 15.20.
A 下午出港。航班15：20起飞。

B Fifteen - twenty? You should get to the airport just after one.
B 15：20？ 你应该1点后就到机场。

Notes 注释
1 For travel times, and the 24-hour clock, we usually say two numbers – the hour then the minutes, eg: (15.20) fifteen - twenty / fifteen - twenty. Or you can say: twenty past three in the afternoon / twenty past three in the afternoon.
对于出行的时间，和24小时制的说法，我们通常用两个数字来说——分别表示小时和分钟。例如: (15.20) fifteen - twenty /15点20分。或者你可以说：twenty past three in the afternoon /下午3点过20分。

Key phrases and sentences
I’m off to Shanghai tomorrow afternoon.
Of course, I forgot.
You’re going to Shanghai, aren’t
you?
Yes, just for the weekend.
I’m back on Monday.
What time’s your flight?
It’s an afternoon departure.
The flight leaves at 15.20.
Fifteen - twenty? You should get to the airport just after one.

我明天下午去上海。
当然，我忘了。
你要去上海，不是吗？
是的，只是度个周末，我周一就回来。
你的航班什么时候起飞？
下午出港。
航班15：20起飞。
15：20？ 你应该1点后就到机场。