不知道 + QW + Verb + 好 (don't know what's best)
"I don't know what's best to do"
- not不to know知道 + (question word) + Verb + good好 = "don't know what / which … is best".
- not不to know知道variant of 说说what什么good好 = "(I) don't know what to say."
- The good好 at the end = "would be best".
not不to know知道 + QW + Verb + good好
- …good好 asks which choice would be the good one.
I我not不know知道buy买which哪个best好。
- not不to know知道to buy买which哪个good好 = "(I) don't know which to buy."
Practice
Don't know which to buy: 我不知道买哪个 ____。
不知道 + QW + Verb + 好 = don't know what's best: 不知道买哪个好.
Practice
This pattern shows the speaker is unsure which option is best.
Yes — it marks a dilemma.
Marks a dilemma
- It shows you're unsure which option is best.
Explore
Correct or broken?
不知道 + QW + verb + 好 wrings hands: can't decide what would be best.
Practice
What does the final 好 add?
…好 = which choice would be best: 不知道说什么好.
Recap
Key idea
- not不to know知道 + QW + Verb + good好 — "don't know what / which … is best"
- not不to know知道variant of 说说what什么good好 · not不to know知道to buy买which哪个good好
- The good好 = "would be best" (a dilemma)
Read the full reference: HSK 4 grammar — Basic sentence patterns.