Now yesterday
can answer back.
You can already say what yesterday was. Add one small question marker and yesterday stops being a private memory. Now you can ask another person about theirs.
Was it?
Keep the polite past statement and add か. Your voice does not need acrobatics; the grammar has already marked the question.
Were you working yesterday?
A tiny question can open an ordinary office conversation. Nothing glamorous. Quite useful—which is often better.
Statement + か.
You are not rebuilding the sentence—just asking whether it was true. でした。 becomes でしたか。
Not every question gets a yes.
The past-negative form from the previous lesson now earns its place in a real exchange.
A question is only half a conversation.
One person asks. The other answers. Then somebody acknowledges what they heard.
Yesterday's work
Female → Male → Female
Yesterday's weather
Male → Female → Male
Meetings and school.
The nouns change while the question frame stays steady.
そうですか。
Sometimes conversation needs only a small signal that says: I heard you.
How was yesterday?
You do not need every possible answer yet. For now, recognise this useful question when you hear it.
Ask one person about yesterday.
Was yesterday a workday? Was there a meeting? Was it rainy? Listen to the answer and try a simple そうですか。 You are making room for somebody else's Japanese too.
A question makes memory social.
Yesterday belonged to one person. A small question made part of it shared. Language sometimes advances through grammar. Sometimes it advances because somebody bothered to ask.