Either…or is a helpful construction used to indicate a choice between options. It can also be difficult to employ it properly. Here are a couple of quick tips for using either…or in your writing.
How many choices?
According to some grammar books, either should be used with only two choices in an either…or construction.
Example: In the General area, the Table direction can be set to either Up or Down.
Example: The arc length can be changed either from the Properties palette or by using the REVCLOUDPROPERTIES command.
In practice, it is often acceptable to use this construction with more than one choice, especially when the intended meaning is still clear. However, you may want to avoid this for some audiences or in more formal writing. The same meaning can often be conveyed by simply omitting the either from the sentence and letting or indicate the choice.
Example: If you want to stretch a dynamic block in one direction, you are required to associate the Stretch action with a Linear, Polar, or XY parameter.
Keep it parallel
One thing that is often incorrect in an either…or sentence is the parallelism. When using this construction, the two choices should be parallel with each other. In other words, they should match each other in structure.
Incorrect: You can use either Batch Plot or plot a single sheet.
Correct: You can either use Batch Plot or plot a single sheet.
The either should be placed so that what follows is the same for both parts of the construction. In the above examples, the verb use only applies to the first option in the construction. It needs to follow either so that both verbs are kept with their objects. A quick trick is to read both parts separately to see if they still make sense without the either…or construction. With the incorrect example, the two sentences would be “You can use Batch Plot” and “You can use plot a single sheet". The second sentence does not make grammatical sense, so the either…or construction is not correctly parallel.
If you’d like other resources for learning more about this construction, please reach out! Or for more grammar tips, check out ASCENT’s Technical Writing resource page.
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