There are numerous ways to inadvertently derail a sentence by failing to provide consistent structure to parallel elements. The following sentences illustrate various types of pitfalls and how they can be avoided.
1. These audits are performed on both an ongoing basis or as part of due diligence.
Both is appropriate (but not required) when a second choice is mentioned in addition but not when the reference is in opposition, as here: “These audits are performed on an ongoing basis or as part of due diligence.”
2. The snakes will be safe from human interference, will have ideal places to hibernate, and plenty of mice and chipmunks to eat.
Each of the three phrases in this sentence requires a verb at the head of the phrase: “The snakes will be safe from human interference, will have ideal places to hibernate, and will have plenty of mice and chipmunks to eat.”
3. Other exhibits include rare movies about San Francisco, a primer on nineteenth-century architecture as well as the twentieth-century history of the city’s gay and lesbian community.
“As well as” is not simply an equivalent substitute for and; it is appropriate only when adding a subordinate clause to a main clause. Also, because the first two items do not constitute a list, they must be connected with a conjunction rather than separated by punctuation: “Other exhibits include rare movies about San Francisco and a primer on nineteenth-century architecture, as well as the twentieth-century history of the city’s gay and lesbian community.”
4. His latest controversial product didn’t receive as much backlash as expected, but hundreds of orders.
The counterpoint in this sentence must, to be parallel, consist of an independent clause, complete with a subject and a verb: “His latest controversial product didn’t receive as much backlash as expected, but it did result in hundreds of orders.”
5. They must either win Tuesday night or Saturday night to return to the finals.
The conjunction either should follow the verb: “They must win either Tuesday night or Saturday night to return to the finals.” (An exception is if each choice in this sentence is preceded by its own verb, as in “They must either win Tuesday night or prevail Saturday night to return to the finals.”)
“Five Types of Error”, surely?
As I read the fourth example sentence, the main clause seems to be ambiguous.
“His latest controversial product didn’t receive much backlash as expected . . .”
That is, it would not have caught my attention if it had been as follows.
“His latest controversial product didn’t receive as much backlash as expected . . .”
PHB
Mark: I assume it’s a typo, #5, where you intended to say that the word “either” should follow the verb (not precede it).
Tony:
In American English, which is my language, “5 Types of Errors” is correct. The style you propose is British English.
Paul:
Thanks for your note. The sentence has been revised to what you have proposed (and what I originally intended to write).
thebluebird11:
Yes, it was an error, which has now been corrected. Thanks for your note.