Learn Dutch: Hebben jullie elk concept goed voorbereid? - Did you all prepare every draft well?

The verb voorbereiden is a separable verb made of the stressed prefix voor- and the verb bereiden. Normally, you put -ge- between the separable prefix and the verb to make a past participle. However, because bereiden already starts with the unstressed inseparable prefix be-, you must omit the -ge- entirely.

Why is it elk concept instead of elke concept?

The word concept is a het word (het concept). When you use words for "every" or "each" with a singular het word, you drop the -e ending, giving you elk. If it were a de word, you would use elke (for example, elke brief).

Does concept mean the same thing as the English word "concept"?

It can mean an abstract idea or concept, but in Dutch business and school contexts, it very often means a "draft" of a document or plan. That is why "draft" fits best in this translation.

Why does voorbereid go at the very end of the sentence?