1.-The authors of computer viruses are geniuses.
-I agree.They can apply their wisdom to other net technology ______human beings can benefit.
A.in which B.through which C.on which D.from which
2.Luckily,we'd bought a map without_____we would have lost our way.
A.it B.that C.this D.which
请详细解答，谢谢

两道题的答案都是D.
这两道题都是关于介词加代词引导定语从句的。这时的定语从句使用什么样的介词，要看该介词在定于从句中所起作用，或与其他词搭配的关系。例如，第一句里from与benefit搭配，组成benefit from‘从…中受益’；第二句里介词without表示‘没有’的意思，后面接代词或名。等于without the map，也就是‘没有这张地图的话，我们就迷路了’。