加上 / 完了: on top of that, afterwards
【五15】连词 / conjunctions
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
加上 and 完了 are two spoken connectors. 加上 adds a second reason to the first one, before the conclusion: 天气不太好，加上你还有作业，我们还是别去了 ("the weather's bad, and you have homework too, so let's not go"). It is close to 而且 (HSK 3), but 而且 simply extends an idea, whereas 加上 piles up reasons that lead to a conclusion (所以, 还是…). So a first reason must always come before it.
完了 means "when that's done, afterwards" and links two actions: 你先写作业，完了我们去公园. It is a spoken relay, shorter and more casual than 然后, and it stresses that the first action is over.
Watch out for look-alikes: the exclamation 完了！ on its own means "that's it, we're doomed!", and V + 完了 (吃完了) means "to have finished doing". Here 完了 sits between two actions and takes no 的话.
Examples
你先写作业，完了我们去公园走走。
Nǐ xiān xiě zuòyè, wán le wǒmen qù gōngyuán zǒuzou.Do your homework first, then we'll go for a walk in the park.
天气不太好，加上你还有作业，我们还是别去了。
Tiānqì bú tài hǎo, jiāshàng nǐ hái yǒu zuòyè, wǒmen háishi bié qù le.The weather isn't great and you've got homework too, so let's not go.
先把菜洗好，完了我来切。
Xiān bǎ cài xǐ hǎo, wán le wǒ lái qiē.Wash the vegetables first, then I'll cut them.
他昨天晚上没睡好，加上早上起得太早，一整天都没精神。
Tā zuótiān wǎnshang méi shuì hǎo, jiāshàng zǎoshang qǐ de tài zǎo, yì zhěngtiān dōu méi jīngshen.He slept badly last night and got up too early this morning, so he's been drained all day.
房租本来就贵，加上交通又不方便，所以很多年轻人不愿意住在这里。
Fángzū běnlái jiù guì, jiāshàng jiāotōng yòu bù fāngbiàn, suǒyǐ hěn duō niánqīngrén bú yuànyì zhù zài zhèlǐ.Rents were high to begin with, and transport is inconvenient too, so many young people don't want to live here.
你把这份文件看一遍，完了告诉我你的想法。
Nǐ bǎ zhè fèn wénjiàn kàn yí biàn, wán le gàosu wǒ nǐ de xiǎngfǎ.Read this document through once, then tell me what you think.
Common mistakes
✗ 加上他很忙，所以他没来 → ✓ 他很累，加上又很忙，所以他没来 (加上 needs a first reason before it).
✗ 先写作业，完了的话我们去公园 → ✓ 先写作业，完了我们去公园 (no 的话 after 完了).
✗ 他很累，加上，所以早睡了 → ✓ 他很累，加上明天要早起，所以早睡了 (加上 is followed by the second reason).