His sister doesn't write a letter to her friend today.（用yesterday替换today） His sister _____
His sister doesn't write a letter to her friend today.（用yesterday替换today）
His sister _____ _____ a letter to her friend yesterday.
Betty and Kevin did their homework last night.（改一般疑问句）
_____ Betty and Kevin _____ their homework last night?
It was sunny the day before yesterday.（用cloudy改选择疑问句）
Was it sunny ____ _____ the day before yesterday?