I asked a student recently to write about something he enjoys doing. He returned with a paragraph on cooking, and here (with his permission) are his final two sentences:
Although cooking seems effortless, it is quite challenging. To achieve the right texture, not undercooked or overcooked, not only one needs to manage the timing precisely, but needs to be inventive—and both requires years of practice and experience.
The first sentence here poses no problem, and I include it mainly for context. But notice how it provides the source idea for the second sentence, which then builds out nicely from it: the first sentence ends with the idea that cooking is challenging, and the second sentence begins with an illustration of that challenge. This is a good example of what I have called backstitching, threading ideas sentence to sentence in order to ensure coherence in a paragraph.
It is the second sentence, though, that requires a closer look. The writer is asserting that the good cook needs two things: to manage timing precisely and to be inventive, and that’s interesting because we don’t usually associate being precise with being imaginative, which is what I take him to mean by inventive. He has written the transitive verb needs twice, and given each instance its direct object.
We can revise this sentence according to two principles: parallelism and concision. Grammatical structures are parallel when they are composed of the same syntax. The two direct objects of needs are both infinitive phrases, and that does indeed meet in part the definition of parallelism. But the writer is also employing here what are called correlative conjunctions, words that work in tandem to keep corresponding ideas together (either…or is probably the most common such pair). If correlatives are not positioned correctly, they undermine the parallelism they are meant to support.
The first of the pair is not only and the second is but, which we should correct to but also. Correlatives work by expectation. When readers see the phrase not only, they know with certainty that a but also will be coming along shortly. That expectation is parallelism at work. But the trick with correlatives is to place them immediately next to the elements they’re coordinating; otherwise, the parallelism slips apart. Thus: one needs not only to manage the timing precisely, but also needs to be inventive. And with that, we’ve realigned the spine of the sentence.
Next we turn to concision. Less is almost always more in writing, so when we find, as we do here, two instances of the same verb, we should ask whether we can combine the two structures into one: so instead of one needs not only to manage the timing precisely, but also needs to be inventive, we write one needs not only to manage the timing precisely, but also to be inventive. That is the second adjustment, according to the principle of concision. Only one minor change remains.
The pronoun both, which refers to the two things an accomplished cook needs, is plural, so its verb, requires, should be corrected to the plural require (because a verb agrees in number with its subject). Thus our complete revision reads like this: To achieve the right texture, not undercooked or overcooked, one needs not only to manage the timing precisely, but also to be inventive—and both require years of practice and experience.
As does grammar.