There were about nine hundred people at the concert(音乐会).(按要求改句子) ______________________________ (否定句) ______________________________ (一般疑问句) ______________________________ (对划线部分提问)
There was only one problem. (按要求改句子) ______________________________ (否定句) ______________________________ (一般疑问句) ______________________________ (对划线部分提问)