Make each question do one job
Where tells the reader a place. When adds a time. Why gives a reason. Asking one question at a time makes the sentence-building task manageable for children who can write a simple sentence but are unsure what to add next.
Point to the scene as you ask each question. When the children suggest a detail, say the complete sentence aloud so they can hear the new information in context.
Keep earlier details as the sentence grows
The important move is carrying information forward. A child first writes the starter with a where phrase, then rewrites it with where and when, and finally includes where, when, and why. The three writing lines make that growth visible.
If a student drops an earlier detail, read the previous line together and ask what the new line should keep. This keeps the feedback focused on meaning instead of correcting every writing convention at once.
Compare sentences, not just answers
The word-help choices allow more than one sensible response. Invite students to share how their details changed the picture in the reader’s mind. Two students can start with the same sentence and end with different fuller versions.
After students understand the routine, the teacher can invite them to suggest their own where, when, or why phrase. The printed choices remain available for writers who still need that support.