What’s wrong with this sentence?
“You can either order coffee or tea.”
This sentence has faulty parallelism. The items joined by the correlative conjunctions
either … or are not in the same grammatical
To see whether a sentence has faulty parallelism, look at the
words or phrases immediately following either and or. In the quoted sentence, the first item is the main verb order; the second item is the noun tea. To correct the sentence, put either after order.
You can order either coffee or
If you need help with parallel constructions, Focus on Grammar: Parallel Constructions is the book to read. When you finish the book, spotting and correcting faulty parallelism will be second nature to you.