Questions & Answers about De zon gaat onder en ik zie hem de code ontcijferen.
Why is gaat onder split up here, but I've seen ondergaan stay together as one word in other sentences?
This is exactly how dual-nature prefixes work! Here, ondergaan means 'to set' (as in the sun setting). It is a separable verb, meaning the stress falls on the prefix (ondergaan), so it splits in a main clause: De zon gaat onder. If it meant 'to undergo', it would be inseparable with the stress on the verb (ondergaan) and wouldn't split.
Can the verb ontcijferen (to decipher) also be split apart in a different context?
No. Unlike onder, the prefix ont- is never separable. Prefixes like be-, ge-, ver-, and ont- are always inseparable and never receive the primary stress. That is why ontcijferen stays solidly together as one word here.
Why is it ik zie hem... ontcijferen without the word te before the infinitive?
Because zien (to see) is a verb of perception. Just like in English ('I see him decipher' rather than 'I see him to decipher'), Dutch verbs of perception like zien, horen (to hear), and voelen (to feel) take a bare infinitive without te.
Why does the verb ontcijferen go all the way at the end of the sentence?