请回答: (1)张骞出使西域的目的是什么? ___________________________________________________________________________________________ (2)张骞通西域后,西域与汉朝的关系如何? ___________________________________________________________________________________________ (3)材料二中的这条通道是指什么?其大致路线是怎样的? ___________________________________________________________________________________________ (4)这条道路的开辟对汉代社会有何影响? ___________________________________________________________________________________________ |