请教OG13 SC107，谢谢各位

Jinnjenny23

这是我在GMAT Club上找到的，Instructor sayantanc2k回答的关于选项B中为什么用的For而不是Of的回答。供大家参考。
Link: https://gmatclub.com/forum/while-it-costs-about-the-same-to-run-nuclear-plants-as-other-134755-60.html

Question: The cost of running A is the same as (the cost) FOR B, not of?
Instructor: Yes, you have a point. Ideally the construction should have been:

The cost of running A is the same as the cost of running B.
Parallel elements:
Cost of running A
Cost of running B.

However, the construction in option B is not grammatically wrong either:

The cost of running  A is the same as (the cost ) for B..(repeated part cost omitted)
Parallel elements:
Cost of running A
Cost for B

In both cases the comparison is between costs. It is not mandatory to maintain parallelism for what follows "cost", i.e. the rest of the two parallel elements.

Let me elaborate a bit more clearly. As long as the comparison is between cost and cost , the sentence is grammatically correct. If the prepositional modifiers of cost are different, then the sentence cannot be said wrong. Nonetheless using similar modifiers is preferred.

cost (of doing) & cost of (thing): NOT illogical.
Cost of eating dinner at XYZ restaurant (say INR 1000) is less than the cost of this bicycle (say INR 5000)..... alright.