Questions & Answers about Ik dacht dat wij samen zouden eten.
Why do we use zouden here instead of zullen?
Because the main action happened in the past (Ik dacht - I thought). When you describe a future plan from a past perspective (like saying "I thought we would..."), you must use the past tense of zullen, which is zouden (or zou for singular subjects), followed by the infinitive eten.
Why is it zouden and not zou?
Zouden is the plural form, and it has to match the subject of the clause it belongs to. Here, the subject of the second part of the sentence is wij (we). If the subject were singular, you would use zou, for example: Ik dacht dat hij zou eten (I thought he would eat).
Why are the verbs zouden and eten pushed all the way to the end?
The word dat (that) introduces a subordinate clause. As a quick refresher: in Dutch subordinate clauses, all the verbs are kicked to the very end of the sentence. That is why samen comes before the verbs.
Can I swap the order of the verbs at the end and say eten zouden?
Yes, you can! When you have two verbs grouped at the end of a subordinate clause, you can usually put the helper verb first (zouden eten) or the main verb first (eten zouden). Both are grammatically correct, though zouden eten is more common and sounds a bit more natural here.