3.The last time I _A_ Jane she ___ cotton in the fields.A.ha

3.The last time I _A_ Jane she ___ cotton in the fields.A.had seen,was picking B.saw,picked C.
上面一题选什么.为什么?（第一空） .再有就是 it's the first time和the first time有什么区别?
3.The last time I __ Jane she ___ cotton in the fields.
A.had seen,was picking B.saw,picked C.had seen,picked D.saw,was picking