Which one do you choose? Two or several options
Put two pens side by side and say どちらですか. Add a third pen and say どれですか. You do not need to name the colours yet: the number of visible choices is the first step.
1. Three or more visible options: どれ
In this lesson's choice setting, どれ stands independently for ‘which one?’. If three or more pens are visible, you can ask ペンはどれですか. The type of object is the topic before は; どれ takes the place of the unidentified item.
A short answer with pointing is これです, それです, or あれです, depending on distance from speaker and listener. To be clearer without pointing, use a noun phrase from lesson 18, such as その白い傘です. どれ does not come directly before a noun; the later pattern どの + noun is only a preview and not a production target here.
ペンはどれですか。
これです。
2. Make a choice identifiable by colour
The colours 白い, 黒い, 赤い, and 青い are い-adjectives and come directly before a noun: 白い傘, 黒いかばん, and 赤いペン. Do not add な. Note the readings しろい for 白い and くろい for 黒い; kanji support recognition and kana support production.
Combine a distance word with the noun phrase when needed: その白い傘です means ‘that white umbrella near you’. The answer then identifies one concrete item. A bare property such as 白いです may be understandable in real context, but the final check deliberately asks for the complete noun phrase.
その白い傘です。
あの黒いかばんです。
3. Two visible options: どちら
When the exercise setting offers exactly two bags, books, or other objects, lesson 19 uses どちら: かばんはどちらですか. Here the question means ‘Which of the two bags is it?’. The number of options comes from the visible or stated context, not from the question word alone.
This is deliberately a different function from lesson 09. There, in a polite school setting, 先生はどちらですか meant ‘Where is the teacher?’. Here, two concrete options are available and どちら asks for a choice. Always look at the situation and expected answer: a place such as 会議室です in lesson 09, or one of two objects in lesson 19.
4. Kind, location, or item?
Three question words can express different information needs with the same noun. どんなかばんですか asks for a description, such as 白いかばんです. かばんはどこですか asks for the location. かばんはどれですか, or どちらですか with two options, asks which item is intended.
Before answering, identify what information the question seeks. A colour can describe a kind and also help identify an item, but the task remains different. In a choice question, your answer points out one concrete thing; a どんな question does not require a row of options.
5. Count, ask, and identify
First make two object cards and ask a どちら question. Add a third and change only the question word to どれ. In both rounds, answer with one distance word and a colour noun phrase. Then explain why the same どちら form could ask for something different in lesson 09.
The final check assesses the number of options and contextual function, followed by a two-option question and a complete identification. The answers are bounded; alternative personal choices in the open application are checked only against criteria.