SC Misconception #8 – ‘Not only’ needs to be followed by ‘but also’

This article is a part of a series of articles on SC Misconceptions. In this series, I’m going to address many misconceptions prevalent among GMAT aspirants.

The misconception addressed in this post is:

‘Not only’ needs to be followed by ‘but also’

However, “not only…but” is also a valid construction. Besides, in some cases, “not only…but” is correct while “not only…but also” is not. Here’s an excerpt from OG 2019 (Page #686)

…there are special cases in which also is unnecessary or misleading. This can be seen in the following sentence: “Surprisingly, the endangered species was found not only at the lowest elevations but throughout the entire valley.” If the lowest elevations referred to are in the valley, but also would misleadingly seem to indicate that the entire valley was a separate category rather than a more general category encompassing the lower elevations.

Let’s further elaborate on the above point. When we say “not only X but also Y”, we mean X and Y are two different entities. However, in the above sentence, X (lower elevations) is a part of Y (throughout the entire valley). Thus, using “not only…but also” in the above sentence would be misleading. It would also be misleading in the below sentence for the same reason:

The president defends not only U.S. sovereignty but the entire world order. (Source: Wsj.com)

In this sentence, ‘U.S. sovereignty’ is a part of ‘the entire world order’. These two entities are not completely separate.

There’s another variation that is acceptable. When “not only” is followed by an independent clause, “but also” can be skipped (Rather, I think that in such cases, we cannot have ‘but’. Not 100% sure though). For example, the following sentence is correct in an official SC question:

As criminal activity on the Internet becomes more and more sophisticated, not only are thieves able to divert cash from company bank accounts, they can also pilfer valuable information such as business development strategies, new product specifications, and contract bidding plans, and sell the data to competitors.

Here’s the link to the detailed solution to this SC question.

I believe this structure, in which you have “not only” without ‘but also’ , is permissible only when you have an independent clause after “not only”, as is the case above. In such cases, the other independent clause does not need to begin with ‘but’ or “but also”.

Please remember that in all other cases, in which “not only” does not contain an independent clause, “not only” needs to be accompanied by ‘but’ or “but also”, and the two elements contained in these two constructs should be logically and grammatically parallel.