1.James has three sisters,all of _____ are married.
a.who b.whom c.them d.which
2.That famous researcher died all of a sudden,_____ the project unfinished.
a.leaving b.left c.leave d.and leaves
3.A backpacking subculture _____ in Kathmandu,Goa,and Bangkok since it became part of the "hippie" routes in the 1960s.
a.exist b.existed c.has existed d.had existed
以上三题请个位高手帮解，我选的答案分别是cdd，在请个位帮我过目一下，谢谢!!!