1.This is the first time that the Turners( )such a beautiful

1.This is the first time that the Turners( )such a beautiful park.
A.have visited B.visit C.has visited D.visited
2.He ( )a novel last year,but l don't know whether he has finished it or not.
A.Wrote B.had written C.has written D.was writing
3.More than a dozen student in our school( )abroad to study English last year.
A.were sent B.was sent
为什么?