把英文句子变成一般疑问句和否定句
1.Wewere15yearoldin1999.
2.ThatwasourdestCDplayerashorttimeago.
3.Daisywasatthedentist'slastSatuday.
4.Thesefunybookswererobert's.
5.Iwasatschoolyesterdaymorring.
6.Thereweresomestudentattheparty.