这题选B对么,若不对,请说明理由32.________ for years,life on other planets is still a mystery for human beings.A.Having been looked for B.Having been looking forC.Having looked for D.Looked for

这题选B对么,若不对,请说明理由32.________ for years,life on other planets is still a mystery for human beings.A.Having been looked for B.Having been looking forC.Having looked for D.Looked for
这题选B对么,若不对,请说明理由
32.________ for years,life on other planets is still a mystery for human beings.
A.Having been looked for B.Having been looking for
C.Having looked for D.Looked for

这题选B对么,若不对,请说明理由32.________ for years,life on other planets is still a mystery for human beings.A.Having been looked for B.Having been looking forC.Having looked for D.Looked for
答案应该是A
1 这道题考察的是非谓语动词的用法,句子的主语是life.根椐题意可知,生命是人去寻找的.因些look for 这个动作应该用被动来表示.
2 因为look for 这个动作已经存在好多年了,而且look for 这个动词在先于is still a mystery 之前就开始了,所以用having been looked for .当非谓语的动作先于主句动作的时候要用having +Vpp的形式.

对的，现在完成进行时，很合适，望采纳