句型转换。
1．Molly was singing at that time．(改为一般疑问旬)
________ Molly ________ at that time?
2．The Greens have worked in China for four years．(对划线部分提问)
________ ________ have the Greens worked?
3．Last year．we planted 110 trees．(改为现在完成时)
So far,we ________ ________ 110 trees．
4．Mary has learnt Italian before．(改为否定句)
Mary ________ ________ Italian before．
5．Mr. Smith has few friends,________ ________?(完成反意疑问句)