who is it playing the piano?是个错句
正确的句子是who is playing the piano?这是对主语提问的特殊疑问句
变成强调句型应该是who is it that is playing the piano?
当然 也许口语中可以把原句看做省略that is的强调句型.不过没见过这种省略
who is it playing the piano?是个错句
正确的句子是who is playing the piano?这是对主语提问的特殊疑问句
变成强调句型应该是who is it that is playing the piano?
当然 也许口语中可以把原句看做省略that is的强调句型.不过没见过这种省略