到底

1. Origins, structure, and basic meaning

• Structure: Written 到底 and read とうてい, it is an adverb that strongly marks something as impossible under the circumstances.
• Basic usage: It is used when a task cannot possibly be finished with the available time or effort.

2. Common pitfalls and similar expressions

• Normally pairs with negation
  • It reinforces expressions such as impossible or cannot, rather than positive possibility.