１課

The grammar point "うちに" is often translated as "while" or "before." It is used to express doing something while a particular condition or state is true, or before that state changes.

Both "てからでないと" and "てからでなければ" express a conditional requirement where a certain action or state cannot happen until a preceding condition has been fulfilled.

"間" (あいだ) and "間に" (あいだに) both convey the idea of an interval or duration in which an action or state occurs.

"ところだ" and "ところ (+ 助詞)" are expressions used to indicate a specific point in time related to an action or event, often focusing on the exact timing.