下去 after a verb means keep the action going from this point on: 说下去 "go on (talking)", 学下去 "keep studying". Where 起来 marks a start, 下去 looks forward — don't stop now.
Slip 不 in the middle and you get "can't bear to continue": 看不下去 "can't keep reading", 听不下去 "can't stand to keep listening". And the literal sense is still alive too: 走下去 can simply mean "walk on down (that way)".
Examples
你说下去,我在听。
你說下去,我在聽。
nǐ shuō xià qù wǒ zài tīng
Go on — I'm listening.
中文很难,但是我想学下去。
中文很難,但是我想學下去。
zhōng wén hěn nán dàn shì wǒ xiǎng xué xià qù
Chinese is hard, but I want to keep studying it.
这本书太没意思了,我看不下去了。
這本書太沒意思了,我看不下去了。
zhè běn shū tài méi yì si le wǒ kàn bù xià qù le
This book is so boring — I can't keep reading it.
从这里走下去,就是火车站。
從這裡走下去,就是火車站。
cóng zhè lǐ zǒu xià qù jiù shì huǒ chē zhàn
Keep walking down from here and you'll hit the train station.
Common mistakes
✗ 我要下去学中文。
✓ 我要学下去。
下去 follows the verb it continues — out in front it just means "go downstairs/down".
Every grammar point in this guide is built into the Literate Chinese app, with graded stories that use the pattern naturally and flashcards matched to the words you know — in Mainland or Taiwan Mandarin. Free on iOS and Android.