何曜日

1. Origins, structure, and basic meaning

• Structure: 何曜日 (なんようび) asks which day of the week. 何曜日ですか is a direct question; 何曜日か is an embedded indirect question.
• Basic usage: One speaker asks for the library's closing day; another checks a notebook for the day of the next class.

2. Common pitfalls and similar expressions

• Day asked directly and day embedded as information
  • Sentence-final ですか requests an answer, whereas nominalizing か marks the information being checked. The second か does not make the whole sentence a direct question.