举报
_雪落_
否定句The farmers aren't singing happily in the field. 一般疑问句Are the farmers singing happily in the field? 括号提问What are the farmers doing ? 否定句Tim isn't writing a letter to his father in America 一般疑问句 Is Tim writing a letter to his father in America? 特殊疑问句 who is Tim writing a letter to ?