prep15 SC Q80 关于平行结构的问题

Yizhiii

Any medical test will sometimes fail to detect a condition when it is present and indicate that there is one when it is not.

(A) a condition when it is present and indicate that there is one

(B) when a condition is present and indicate that there is one

(C) a condition when it is present and indicate that it is present

(D) when a condition is present and indicate its presence

(E) the presence of a condition when it is there and indicate

正确答案是选C，有个疑问，为什么“fail to detect a condition when it is present” 与 “ indicate that it is present when it is not”是平行的结构？简化点就是“fail to detect a condition”为什么与“indicate that it is present”这是平行的，一个有从句一个没有啊。

Fiona09

题干划线最后其实是省略了一个present, 即when it is not present。这是和前面的when it is present构成的平行