Two flights, two prices, two getting-up times. Chen Hao has compared them; Xiaoyu decides.
Chen Hao
下个月的机票，你买了吗？
Xià gè yuè de jīpiào, nǐ mǎi le ma ?
Have you bought your plane ticket for next month?
Xiaoyu
还没有。我正在看，价格天天在变。
Hái méiyǒu. Wǒ zhèngzài kàn, jiàgé tiāntiān zài biàn.
Not yet. I am looking, the prices change every day.
Chen Hao
早上八点的那班最便宜，只要四百八十。
Zǎoshang bā diǎn de nà bān zuì piányi, zhī yào sìbǎi bāshí.
The eight in the morning is the cheapest, only four hundred and eighty.
Xiaoyu
八点的太早了，四点就得起床。
Bā diǎn de tài zǎo le, sì diǎn jiù de qǐchuáng.
Eight is too early, we would have to get up at four.
Chen Hao
下午两点的贵一百，可是不用早起。
Xiàwǔ liǎng diǎn de guì yībǎi, kěshì bù yòng zǎo qǐ.
The two in the afternoon is a hundred dearer, but you do not have to get up early.
Xiaoyu
那就买下午的吧。几个小时到？
Nà jiù mǎi xiàwǔ de ba. Jǐ gè xiǎoshí dào ?
Then let us take the afternoon one. How long does it take?
Chen Hao
两个半小时，五点以前就到家了。
Liǎng gè bàn xiǎoshí, wǔ diǎn yǐqián jiù dào jiā le.
Two and a half hours, we would be home before five.
Xiaoyu
行李可以带多少？
Xíngli kěyǐ dài duōshao ?
How much luggage are we allowed?
Chen Hao
二十公斤，你的箱子别超过就行。
Èrshí gōngjīn, nǐ de xiāngzi bié chāoguò jiù xíng.
Twenty kilos, just make sure your case does not go over.
Xiaoyu
我的空箱子就五公斤，没问题。
Wǒ de kōng xiāngzi jiù wǔ gōngjīn, méi wèntí.
My case weighs five kilos empty, no danger there.
Chen Hao
那我现在就订，订好发给你。
Nà wǒ xiànzài jiù dìng, dìng hǎo fā gěi nǐ.
Then I will book now and send it to you once it is done.
Flights and trains are counted in 班, which names a scheduled service and not the vehicle: 那班飞机, that flight; 第一班车, the first departure. The same word does for shifts at work, 上班 and 下班, to start and to leave your shift, and for a class of pupils. What it has in common everywhere is the idea of a group taking its turn at a fixed hour.
四点就得起床: as early as four, which is hard. 五点以前就到家了: by five you are already home, which is convenient. In both cases the same 就 marks that the moment comes earlier than expected, but the judgement changes with the sentence: painful for the alarm clock, pleasant for the arrival. Its opposite is 才, which always says "not before".
订好发给你 puts two actions end to end in their real order: book, then send. Chinese puts in neither "and" nor "then" when the sequence is obvious, and the first verb carries its complement of result, 好, which is enough to say that the second action waits for the first to finish.
